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ext4: xattr-in-inode support

PATCH Superseded Tahsin Erdogan 6 participants 80 messages May 31, 2017 – Jul 6, 2017 Page 1 of 2

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#0 lore raw

PATCH 1/28 ext4: xattr-in-inode support

From: Andreas Dilger <[email protected]>

Large xattr support is implemented for EXT4_FEATURE_INCOMPAT_EA_INODE.

If the size of an xattr value is larger than will fit in a single external block, then the xattr value will be saved into the body of an external xattr inode.

The also helps support a larger number of xattr, since only the headers will be stored in the in-inode space or the single external block.

The inode is referenced from the xattr header via "e_value_inum", which was formerly "e_value_block", but that field was never used. The e_value_size still contains the xattr size so that listing xattrs does not need to look up the inode if the data is not accessed.

struct ext4_xattr_entry {

        __u8    e_name_len;     /* length of name */
        __u8    e_name_index;   /* attribute name index */
        __le16  e_value_offs;   /* offset in disk block of value */
        __le32  e_value_inum;   /* inode in which value is stored */
        __le32  e_value_size;   /* size of attribute value */
        __le32  e_hash;         /* hash value of name and value */
        char    e_name[0];      /* attribute name */

};

The xattr inode is marked with the EXT4_EA_INODE_FL flag and also holds a back-reference to the owning inode in its i_mtime field, allowing the ext4/e2fsck to verify the correct inode is accessed.

Lustre-Jira: https://jira.hpdd.intel.com/browse/LU-80
Lustre-bugzilla: https://bugzilla.lustre.org/show_bug.cgi?id=4424

---
 fs/ext4/ext4.h   |  12 ++
 fs/ext4/ialloc.c |   1 -
 fs/ext4/inline.c |   2 +-
 fs/ext4/inode.c  |  49 ++++-
 fs/ext4/xattr.c  | 565 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
 fs/ext4/xattr.h  |  33 +++-
 6 files changed, 606 insertions(+), 56 deletions(-)
fs/ext4/ext4.h +12 -0
index 32191548abed..24ef56b4572f 100644
@@ -1797,6 +1797,7 @@ EXT4_FEATURE_INCOMPAT_FUNCS(encrypt,		ENCRYPT)
 					 EXT4_FEATURE_INCOMPAT_EXTENTS| \
 					 EXT4_FEATURE_INCOMPAT_64BIT| \
 					 EXT4_FEATURE_INCOMPAT_FLEX_BG| \
+					 EXT4_FEATURE_INCOMPAT_EA_INODE| \
 					 EXT4_FEATURE_INCOMPAT_MMP | \
 					 EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
 					 EXT4_FEATURE_INCOMPAT_ENCRYPT | \
@@ -2220,6 +2221,12 @@ struct mmpd_data {
 #define EXT4_MMP_MAX_CHECK_INTERVAL	300UL
 
 /*
+ * Maximum size of xattr attributes for FEATURE_INCOMPAT_EA_INODE 1Mb
+ * This limit is arbitrary, but is reasonable for the xattr API.
+ */
+#define EXT4_XATTR_MAX_LARGE_EA_SIZE    (1024 * 1024)
+
+/*
  * Function prototypes
  */
 
@@ -2231,6 +2238,10 @@ struct mmpd_data {
 # define ATTRIB_NORET	__attribute__((noreturn))
 # define NORET_AND	noreturn,
 
+struct ext4_xattr_ino_array {
+	unsigned int xia_count;		/* # of used item in the array */
+	unsigned int xia_inodes[0];
+};
 /* bitmap.c */
 extern unsigned int ext4_count_free(char *bitmap, unsigned numchars);
 void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
@@ -2478,6 +2489,7 @@ extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
 extern void ext4_set_inode_flags(struct inode *);
 extern int ext4_alloc_da_blocks(struct inode *inode);
 extern void ext4_set_aops(struct inode *inode);
+extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int chunk);
 extern int ext4_writepage_trans_blocks(struct inode *);
 extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
 extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
fs/ext4/ialloc.c +0 -1
index 98ac2f1f23b3..e2eb3cc06820 100644
@@ -294,7 +294,6 @@ void ext4_free_inode(handle_t *handle, struct inode *inode)
 	 * as writing the quota to disk may need the lock as well.
 	 */
 	dquot_initialize(inode);
-	ext4_xattr_delete_inode(handle, inode);
 	dquot_free_inode(inode);
 	dquot_drop(inode);
 
fs/ext4/inline.c +1 -1
index 8d141c0c8ff9..28c5c3abddb3 100644
@@ -61,7 +61,7 @@ static int get_max_inline_xattr_value_size(struct inode *inode,
 
 	/* Compute min_offs. */
 	for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
-		if (!entry->e_value_block && entry->e_value_size) {
+		if (!entry->e_value_inum && entry->e_value_size) {
 			size_t offs = le16_to_cpu(entry->e_value_offs);
 			if (offs < min_offs)
 				min_offs = offs;
fs/ext4/inode.c +40 -9

96 lines not on this page · raw message

fs/ext4/xattr.c +523 -42

794 lines not on this page · raw message

fs/ext4/xattr.h +30 -3
index 099c8b670ef5..6e10ff9393d4 100644
@@ -44,7 +44,7 @@ struct ext4_xattr_entry {
 	__u8	e_name_len;	/* length of name */
 	__u8	e_name_index;	/* attribute name index */
 	__le16	e_value_offs;	/* offset in disk block of value */
-	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
+	__le32	e_value_inum;	/* inode in which the value is stored */
 	__le32	e_value_size;	/* size of attribute value */
 	__le32	e_hash;		/* hash value of name and value */
 	char	e_name[0];	/* attribute name */
@@ -69,6 +69,26 @@ struct ext4_xattr_entry {
 		EXT4_I(inode)->i_extra_isize))
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
+/*
+ * Link EA inode back to parent one using i_mtime field.
+ * Extra integer type conversion added to ignore higher
+ * bits in i_mtime.tv_sec which might be set by ext4_get()
+ */
+#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
+do {                                                  \
+      (inode)->i_mtime.tv_sec = inum;                 \
+} while(0)
+
+#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
+((__u32)(inode)->i_mtime.tv_sec)
+
+/*
+ * The minimum size of EA value when you start storing it in an external inode
+ * size of block - size of header - size of 1 entry - 4 null bytes
+*/
+#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b)					\
+	((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)
+
 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
@@ -77,10 +97,11 @@ struct ext4_xattr_entry {
 #define EXT4_ZERO_XATTR_VALUE ((void *)-1)
 
 struct ext4_xattr_info {
-	int name_index;
 	const char *name;
 	const void *value;
 	size_t value_len;
+	int name_index;
+	int in_inode;
 };
 
 struct ext4_xattr_search {
@@ -140,7 +161,13 @@ extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
 
-extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
+extern struct inode *ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
+					   int *err);
+extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
+extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+				   struct ext4_xattr_ino_array **array);
+extern void ext4_xattr_inode_array_free(struct inode *inode,
+					struct ext4_xattr_ino_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 			    struct ext4_inode *raw_inode, handle_t *handle);
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#1 lore raw

PATCH 2/28 ext4: fix lockdep warning about recursive inode locking

Setting a large xattr value may require writing the attribute contents to an external inode. In this case we may need to lock the xattr inode along with the parent inode. This doesn't pose a deadlock risk because xattr inodes are not directly visible to the user and their access is restricted.

Assign a lockdep subclass to xattr inode's lock.

============================================
WARNING: possible recursive locking detected
4.12.0-rc1+ #740 Not tainted
--------------------------------------------
python/1822 is trying to acquire lock:
(&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff804912ca>] ext4_xattr_set_entry+0x65a/0x7b0

but task is already holding lock:
(&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803d6687>] vfs_setxattr+0x57/0xb0

other info that might help us debug this:

  Possible unsafe locking scenario:
        CPU0
        ----

lock(&sb->s_type->i_mutex_key#15);
lock(&sb->s_type->i_mutex_key#15);

*** DEADLOCK ***

May be due to missing lock nesting notation

4 locks held by python/1822:

  #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff803d0eef>] mnt_want_write+0x1f/0x50
  #1:  (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803d6687>] vfs_setxattr+0x57/0xb0
  #2:  (jbd2_handle){.+.+..}, at: [<ffffffff80493f40>] start_this_handle+0xf0/0x420
  #3:  (&ei->xattr_sem){++++..}, at: [<ffffffff804920ba>] ext4_xattr_set_handle+0x9a/0x4f0
 stack backtrace:
 CPU: 0 PID: 1822 Comm: python Not tainted 4.12.0-rc1+ #740
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 Call Trace:
  dump_stack+0x67/0x9e
  __lock_acquire+0x5f3/0x1750
  lock_acquire+0xb5/0x1d0
  down_write+0x2c/0x60
  ext4_xattr_set_entry+0x65a/0x7b0
  ext4_xattr_block_set+0x1b2/0x9b0
  ext4_xattr_set_handle+0x322/0x4f0
  ext4_xattr_set+0x144/0x1a0
  ext4_xattr_user_set+0x34/0x40
  __vfs_setxattr+0x66/0x80
  __vfs_setxattr_noperm+0x69/0x1c0
  vfs_setxattr+0xa2/0xb0
  setxattr+0x12e/0x150
  path_setxattr+0x87/0xb0
  SyS_setxattr+0xf/0x20
  entry_SYSCALL_64_fastpath+0x18/0xad
---
 fs/ext4/inode.c | 2 ++
 fs/ext4/xattr.c | 8 ++++++++
 fs/ext4/xattr.h | 6 ++++++
 3 files changed, 16 insertions(+)
fs/ext4/inode.c +2 -0
index e5535e5b3dc5..d095bf7ad390 100644
@@ -4877,6 +4877,8 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
+	if (ei->i_flags & EXT4_EA_INODE_FL)
+		ext4_xattr_inode_set_class(inode);
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/xattr.c +8 -0
index 444be5c7a1d5..26d2705950a5 100644
@@ -107,6 +107,13 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 #define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
 				inode->i_sb->s_fs_info)->s_mb_cache)
 
+#ifdef CONFIG_LOCKDEP
+void ext4_xattr_inode_set_class(struct inode *ea_inode)
+{
+	lockdep_set_subclass(&ea_inode->i_rwsem, 1);
+}
+#endif
+
 static __le32 ext4_xattr_block_csum(struct inode *inode,
 				    sector_t block_nr,
 				    struct ext4_xattr_header *hdr)
@@ -830,6 +837,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 		ea_inode->i_op = &ext4_file_inode_operations;
 		ea_inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(ea_inode);
+		ext4_xattr_inode_set_class(ea_inode);
 		ea_inode->i_generation = inode->i_generation;
 		EXT4_I(ea_inode)->i_flags |= EXT4_EA_INODE_FL;
 
fs/ext4/xattr.h +6 -0
index 6e10ff9393d4..e8bef79bdc38 100644
@@ -196,3 +196,9 @@ static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 	return 0;
 }
 #endif
+
+#ifdef CONFIG_LOCKDEP
+extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
+#else
+static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
+#endif
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#2 lore raw

PATCH 3/28 ext4: lock inode before calling ext4_orphan_add()

In reply to Tahsin Erdogan

ext4_orphan_add() requires caller to be holding the inode lock. Add missing lock statements.

 WARNING: CPU: 3 PID: 1806 at fs/ext4/namei.c:2731 ext4_orphan_add+0x4e/0x240
 CPU: 3 PID: 1806 Comm: python Not tainted 4.12.0-rc1+ #746
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 task: ffff880135d466c0 task.stack: ffffc900014b0000
 RIP: 0010:ext4_orphan_add+0x4e/0x240
 RSP: 0018:ffffc900014b3d50 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff8801348fe1f0 RCX: ffffc900014b3c64
 RDX: 0000000000000000 RSI: ffff8801348fe1f0 RDI: ffff8801348fe1f0
 RBP: ffffc900014b3da0 R08: 0000000000000000 R09: ffffffff80e82025
 R10: 0000000000004692 R11: 000000000000468d R12: ffff880137598000
 R13: ffff880137217000 R14: ffff880134ac58d0 R15: 0000000000000000
 FS:  00007fc50f09e740(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00000000008bc2e0 CR3: 00000001375ac000 CR4: 00000000000006e0
 Call Trace:
  ext4_xattr_inode_orphan_add.constprop.19+0x9d/0xf0
  ext4_xattr_delete_inode+0x1c4/0x2f0
  ext4_evict_inode+0x15a/0x7f0
  evict+0xc0/0x1a0
  iput+0x16a/0x270
  do_unlinkat+0x172/0x290
  SyS_unlink+0x11/0x20
  entry_SYSCALL_64_fastpath+0x18/0xad
---
 fs/ext4/xattr.c | 2 ++
 1 file changed, 2 insertions(+)
fs/ext4/xattr.c +2 -0
index 26d2705950a5..09ba0137d529 100644
@@ -1963,7 +1963,9 @@ ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode,
 				lea_ino_array->xia_inodes[idx], &error);
 		if (error)
 			continue;
+		inode_lock(ea_inode);
 		ext4_orphan_add(handle, ea_inode);
+		inode_unlock(ea_inode);
 		/* the inode's i_count will be released by caller */
 	}
 
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#3 lore raw

PATCH 4/28 ext4: do not set posix acls on xattr inodes

In reply to Tahsin Erdogan

We don't need acls on xattr inodes because they are not directly accessible from user mode.

Besides lockdep complains about recursive locking of xattr_sem as seen below.

=============================================
[ INFO: possible recursive locking detected ]
4.11.0-rc8+ #402 Not tainted
---------------------------------------------
python/1894 is trying to acquire lock:
(&ei->xattr_sem){++++..}, at: [<ffffffff804878a6>] ext4_xattr_get+0x66/0x270

but task is already holding lock:
(&ei->xattr_sem){++++..}, at: [<ffffffff80489500>] ext4_xattr_set_handle+0xa0/0x5d0

other info that might help us debug this:

   Possible unsafe locking scenario:
         CPU0
         ----
    lock(&ei->xattr_sem);
    lock(&ei->xattr_sem);

*** DEADLOCK ***

May be due to missing lock nesting notation

3 locks held by python/1894:

   #0:  (sb_writers#10){.+.+.+}, at: [<ffffffff803d829f>] mnt_want_write+0x1f/0x50
   #1:  (&sb->s_type->i_mutex_key#15){+.+...}, at: [<ffffffff803dda27>] vfs_setxattr+0x57/0xb0
   #2:  (&ei->xattr_sem){++++..}, at: [<ffffffff80489500>] ext4_xattr_set_handle+0xa0/0x5d0
  stack backtrace:
  CPU: 0 PID: 1894 Comm: python Not tainted 4.11.0-rc8+ #402
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
   dump_stack+0x67/0x99
   __lock_acquire+0x5f3/0x1830
   lock_acquire+0xb5/0x1d0
   down_read+0x2f/0x60
   ext4_xattr_get+0x66/0x270
   ext4_get_acl+0x43/0x1e0
   get_acl+0x72/0xf0
   posix_acl_create+0x5e/0x170
   ext4_init_acl+0x21/0xc0
   __ext4_new_inode+0xffd/0x16b0
   ext4_xattr_set_entry+0x5ea/0xb70
   ext4_xattr_block_set+0x1b5/0x970
   ext4_xattr_set_handle+0x351/0x5d0
   ext4_xattr_set+0x124/0x180
   ext4_xattr_user_set+0x34/0x40
   __vfs_setxattr+0x66/0x80
   __vfs_setxattr_noperm+0x69/0x1c0
   vfs_setxattr+0xa2/0xb0
   setxattr+0x129/0x160
   path_setxattr+0x87/0xb0
   SyS_setxattr+0xf/0x20
   entry_SYSCALL_64_fastpath+0x18/0xad
---
 fs/ext4/ext4.h    | 11 ++++++-----
 fs/ext4/ialloc.c  | 14 +++++++++-----
 fs/ext4/migrate.c |  2 +-
 fs/ext4/xattr.c   |  3 ++-
 4 files changed, 18 insertions(+), 12 deletions(-)
fs/ext4/ext4.h +6 -5
index 24ef56b4572f..5d5fc0d0e2bc 100644
@@ -2400,16 +2400,17 @@ extern int ext4fs_dirhash(const char *name, int len, struct
 /* ialloc.c */
 extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
 				      const struct qstr *qstr, __u32 goal,
-				      uid_t *owner, int handle_type,
-				      unsigned int line_no, int nblocks);
+				      uid_t *owner, __u32 i_flags,
+				      int handle_type, unsigned int line_no,
+				      int nblocks);
 
-#define ext4_new_inode(handle, dir, mode, qstr, goal, owner) \
+#define ext4_new_inode(handle, dir, mode, qstr, goal, owner, i_flags) \
 	__ext4_new_inode((handle), (dir), (mode), (qstr), (goal), (owner), \
-			 0, 0, 0)
+			 i_flags, 0, 0, 0)
 #define ext4_new_inode_start_handle(dir, mode, qstr, goal, owner, \
 				    type, nblocks)		    \
 	__ext4_new_inode(NULL, (dir), (mode), (qstr), (goal), (owner), \
-			 (type), __LINE__, (nblocks))
+			 0, (type), __LINE__, (nblocks))
 
 
 extern void ext4_free_inode(handle_t *, struct inode *);
fs/ext4/ialloc.c +9 -5
index e2eb3cc06820..fb1b3df17f6e 100644
@@ -742,8 +742,9 @@ static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
  */
 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 			       umode_t mode, const struct qstr *qstr,
-			       __u32 goal, uid_t *owner, int handle_type,
-			       unsigned int line_no, int nblocks)
+			       __u32 goal, uid_t *owner, __u32 i_flags,
+			       int handle_type, unsigned int line_no,
+			       int nblocks)
 {
 	struct super_block *sb;
 	struct buffer_head *inode_bitmap_bh = NULL;
@@ -1052,6 +1053,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 	/* Don't inherit extent flag from directory, amongst others. */
 	ei->i_flags =
 		ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
+	ei->i_flags |= i_flags;
 	ei->i_file_acl = 0;
 	ei->i_dtime = 0;
 	ei->i_block_group = group;
@@ -1108,9 +1110,11 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 			goto fail_free_drop;
 	}
 
-	err = ext4_init_acl(handle, inode, dir);
-	if (err)
-		goto fail_free_drop;
+	if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
+		err = ext4_init_acl(handle, inode, dir);
+		if (err)
+			goto fail_free_drop;
+	}
 
 	err = ext4_init_security(handle, inode, dir, qstr);
 	if (err)
fs/ext4/migrate.c +1 -1
index 364ea4d4a943..cf5181b62df1 100644
@@ -475,7 +475,7 @@ int ext4_ext_migrate(struct inode *inode)
 	owner[0] = i_uid_read(inode);
 	owner[1] = i_gid_read(inode);
 	tmp_inode = ext4_new_inode(handle, d_inode(inode->i_sb->s_root),
-				   S_IFREG, NULL, goal, owner);
+				   S_IFREG, NULL, goal, owner, 0);
 	if (IS_ERR(tmp_inode)) {
 		retval = PTR_ERR(tmp_inode);
 		ext4_journal_stop(handle);
fs/ext4/xattr.c +2 -1
index 09ba0137d529..12210fe87ea3 100644
@@ -832,7 +832,8 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 	 * in the same group, or nearby one.
 	 */
 	ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
-				  S_IFREG | 0600, NULL, inode->i_ino + 1, NULL);
+				  S_IFREG | 0600, NULL, inode->i_ino + 1, NULL,
+				  EXT4_EA_INODE_FL);
 	if (!IS_ERR(ea_inode)) {
 		ea_inode->i_op = &ext4_file_inode_operations;
 		ea_inode->i_fop = &ext4_file_operations;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#4 lore raw

PATCH 5/28 ext4: attach jinode after creation of xattr inode

In reply to Tahsin Erdogan

In data=ordered mode jinode needs to be attached to the xattr inode when writing data to it. Attachment normally occurs during file open for regular files. Since we are not using file interface to write to the xattr inode, the jinode attach needs to be done manually.

Otherwise the following crash occurs in data=ordered mode.

 BUG: unable to handle kernel NULL pointer dereference at           (null)
 IP: jbd2_journal_file_inode+0x37/0x110
 PGD 13b3c0067
 P4D 13b3c0067
 PUD 137660067
 PMD 0

 Oops: 0000 [#1] SMP
 CPU: 3 PID: 1877 Comm: python Not tainted 4.12.0-rc1+ #749
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 task: ffff88010e368980 task.stack: ffffc90000374000
 RIP: 0010:jbd2_journal_file_inode+0x37/0x110
 RSP: 0018:ffffc90000377980 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff880123b06230 RCX: 0000000000280000
 RDX: 0000000000000006 RSI: 0000000000000000 RDI: ffff88012c8585d0
 RBP: ffffc900003779b0 R08: 0000000000000202 R09: 0000000000000001
 R10: 0000000000000000 R11: 0000000000000400 R12: ffff8801111f81c0
 R13: ffff88013b2b6800 R14: ffffc90000377ab0 R15: 0000000000000001
 FS:  00007f0c99b77740(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 0000000136d91000 CR4: 00000000000006e0
 Call Trace:
  jbd2_journal_inode_add_write+0xe/0x10
  ext4_map_blocks+0x59e/0x620
  ext4_xattr_set_entry+0x501/0x7d0
  ext4_xattr_block_set+0x1b2/0x9b0
  ext4_xattr_set_handle+0x322/0x4f0
  ext4_xattr_set+0x144/0x1a0
  ext4_xattr_user_set+0x34/0x40
  __vfs_setxattr+0x66/0x80
  __vfs_setxattr_noperm+0x69/0x1c0
  vfs_setxattr+0xa2/0xb0
  setxattr+0x12e/0x150
  path_setxattr+0x87/0xb0
  SyS_setxattr+0xf/0x20
  entry_SYSCALL_64_fastpath+0x18/0xad
---
 fs/ext4/xattr.c | 6 ++++++
 1 file changed, 6 insertions(+)
fs/ext4/xattr.c +6 -0
index 12210fe87ea3..8e123533315f 100644
@@ -826,6 +826,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 					     struct inode *inode)
 {
 	struct inode *ea_inode = NULL;
+	int err;
 
 	/*
 	 * Let the next inode be the goal, so we try and allocate the EA inode
@@ -848,6 +849,11 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 		 */
 		EXT4_XATTR_INODE_SET_PARENT(ea_inode, inode->i_ino);
 		unlock_new_inode(ea_inode);
+		err = ext4_inode_attach_jinode(ea_inode);
+		if (err) {
+			iput(ea_inode);
+			return ERR_PTR(err);
+		}
 	}
 
 	return ea_inode;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#5 lore raw

PATCH 6/28 ext4: ea_inode owner should be the same as the inode owner

In reply to Tahsin Erdogan

Quota charging is based on the ownership of the inode. Currently, the xattr inode owner is set to the caller which may be different from the parent inode owner. This is inconsistent with how quota is charged for xattr block and regular data block writes.

---
 fs/ext4/xattr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
fs/ext4/xattr.c +2 -1
index 8e123533315f..32ad2f2870e9 100644
@@ -826,6 +826,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 					     struct inode *inode)
 {
 	struct inode *ea_inode = NULL;
+	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
 	int err;
 
 	/*
@@ -833,7 +834,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 	 * in the same group, or nearby one.
 	 */
 	ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
-				  S_IFREG | 0600, NULL, inode->i_ino + 1, NULL,
+				  S_IFREG | 0600, NULL, inode->i_ino + 1, owner,
 				  EXT4_EA_INODE_FL);
 	if (!IS_ERR(ea_inode)) {
 		ea_inode->i_op = &ext4_file_inode_operations;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#6 lore raw

PATCH 7/28 ext4: call journal revoke when freeing ea_inode blocks

In reply to Tahsin Erdogan

ea_inode contents are treated as metadata, that's why it is journaled during initial writes. Failing to call revoke during freeing could cause user data to be overwritten with original ea_inode contents during journal replay.

---
 fs/ext4/extents.c  | 3 ++-
 fs/ext4/indirect.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)
fs/ext4/extents.c +2 -1
index 3e36508610b7..e0a8425ff74d 100644
@@ -2488,7 +2488,8 @@ int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
 
 static inline int get_default_free_blocks_flags(struct inode *inode)
 {
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
 		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
 	else if (ext4_should_journal_data(inode))
 		return EXT4_FREE_BLOCKS_FORGET;
fs/ext4/indirect.c +2 -1
index bc15c2c17633..7ffa290cbb8e 100644
@@ -829,7 +829,8 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
 	int	flags = EXT4_FREE_BLOCKS_VALIDATED;
 	int	err;
 
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
 		flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
 	else if (ext4_should_journal_data(inode))
 		flags |= EXT4_FREE_BLOCKS_FORGET;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#7 lore raw

Re: [PATCH 07/28] ext4: call journal revoke when freeing ea_inode blocks

Quoted 30 lines · Tahsin Erdogan

ea_inode contents are treated as metadata, that's why it is journaled during initial writes. Failing to call revoke during freeing could cause user data to be overwritten with original ea_inode contents during journal replay.

---
 fs/ext4/extents.c  | 3 ++-
 fs/ext4/indirect.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)
fs/ext4/extents.c +2 -1
index 3e36508610b7..e0a8425ff74d 100644
@@ -2488,7 +2488,8 @@ int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
 
 static inline int get_default_free_blocks_flags(struct inode *inode)
 {
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
 		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
 	else if (ext4_should_journal_data(inode))
 		return EXT4_FREE_BLOCKS_FORGET;
fs/ext4/indirect.c +0 -0
index bc15c2c17633..7ffa290cbb8e 100644

fs/ext4/indirect.c static int ext4_clear_blocks(handle_t *handle, struct inode *inode, · line 833

Quoted 6 lines
fs/ext4/indirect.c +2 -1
@@ -829,7 +829,8 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
 	int	flags = EXT4_FREE_BLOCKS_VALIDATED;
 	int	err;
 
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))

I appreciate the thoroughness of doing this even for blockmapped ea_inode files, and I'm not complaining about this hunk at all. :)

However, please consider requiring the extents feature + format as a prerequisite for ea_inodes. ext4 has traditionally been very ... permissive about supporting a diverse range of feature options, but the cost of that diversity is that the feature support matrix that the community has to support is already untestably large.

I think it would be wise not to support !extents && ea_inode, particularly since blockmaps aren't protected by metadata_csum and so in the long run it's probably best to minimize the introduction of new blockmap files (on ext4 anyway).

--D

Quoted 6 lines
fs/ext4/indirect.c +0 -0
 		flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
 	else if (ext4_should_journal_data(inode))
 		flags |= EXT4_FREE_BLOCKS_FORGET;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#8 lore raw

Re: [PATCH 07/28] ext4: call journal revoke when freeing ea_inode blocks

Quoted 4 lines

I think it would be wise not to support !extents && ea_inode, particularly since blockmaps aren't protected by metadata_csum and so in the long run it's probably best to minimize the introduction of new blockmap files (on ext4 anyway).

Sounds good. I will add that to e2fsprogs patches. thanks

#9 lore raw

Re: [PATCH 07/28] ext4: call journal revoke when freeing ea_inode blocks

In reply to Darrick J. Wong
Quoted 48 lines · Darrick J. Wong
Quoted 30 lines · Tahsin Erdogan

ea_inode contents are treated as metadata, that's why it is journaled during initial writes. Failing to call revoke during freeing could cause user data to be overwritten with original ea_inode contents during journal replay.

---
fs/ext4/extents.c | 3 ++-
fs/ext4/indirect.c | 3 ++-

2 files changed, 4 insertions(+), 2 deletions(-)
fs/ext4/extents.c +2 -1
index 3e36508610b7..e0a8425ff74d 100644
@@ -2488,7 +2488,8 @@ int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
 
 static inline int get_default_free_blocks_flags(struct inode *inode)
 {
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
 		return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
 	else if (ext4_should_journal_data(inode))
 		return EXT4_FREE_BLOCKS_FORGET;
fs/ext4/indirect.c +0 -0
index bc15c2c17633..7ffa290cbb8e 100644

fs/ext4/indirect.c static int ext4_clear_blocks(handle_t *handle, struct inode *inode, · line 833

Quoted 6 lines
fs/ext4/indirect.c +2 -1
@@ -829,7 +829,8 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
 	int	flags = EXT4_FREE_BLOCKS_VALIDATED;
 	int	err;
 
-	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
+	if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
+	    ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))

I appreciate the thoroughness of doing this even for blockmapped ea_inode files, and I'm not complaining about this hunk at all. :)

However, please consider requiring the extents feature + format as a prerequisite for ea_inodes. ext4 has traditionally been very ... permissive about supporting a diverse range of feature options, but the cost of that diversity is that the feature support matrix that the community has to support is already untestably large.

Quoted 4 lines

I think it would be wise not to support !extents && ea_inode, particularly since blockmaps aren't protected by metadata_csum and so in the long run it's probably best to minimize the introduction of new blockmap files (on ext4 anyway).

Sorry, I have to disagree on this one.

The Lustre code ONLY uses the xattr inode with non-extent (indirect) mapped inodes on the metadata target. This is because the MDT only stores inodes and directories (and a handful of regular files) that don't benefit from extents at all, but rather are hurt because directory blocks are typically allocated incrementally over time and result in fragmented block numbers. In this case, extents can increase the dir size by 3x over indirect mapped files without any benefit.

Since the MDT only holds inodes, it never needs to be larger than 16TB (by default only 2KB/inode gives a max MDT size of 8TB) so there is no need for more than 2^32 blocks in the filesystem.

Cheers, Andreas

Quoted 8 lines

--D

Quoted 5 lines
fs/ext4/indirect.c +0 -1
 		flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
 	else if (ext4_should_journal_data(inode))
 		flags |= EXT4_FREE_BLOCKS_FORGET;
--

2.13.0.219.gdb65acc882-goog

Cheers, Andreas

#10 lore raw

PATCH 8/28 ext4: fix ref counting for ea_inode

In reply to Tahsin Erdogan

The ref count on ea_inode is incremented by ext4_xattr_inode_orphan_add() which is supposed to be decremented by ext4_xattr_inode_array_free(). The decrement is conditioned on whether the ea_inode is currently on the orphan list. However, the orphan list addition only happens when journaling is enabled. In non-journaled case,r we fail to release the ref count causing an error message like below.

"VFS: Busy inodes after unmount of sdb. Self-destruct in 5 seconds. Have a nice day..."

---
 fs/ext4/xattr.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
fs/ext4/xattr.c +1 -2
index 32ad2f2870e9..13daf634244b 100644
@@ -2098,8 +2098,7 @@ ext4_xattr_inode_array_free(struct inode *inode,
 		if (err)
 			continue;
 		/* for inode's i_count get from ext4_xattr_delete_inode */
-		if (!list_empty(&EXT4_I(ea_inode)->i_orphan))
-			iput(ea_inode);
+		iput(ea_inode);
 		clear_nlink(ea_inode);
 		iput(ea_inode);
 	}
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#11 lore raw

PATCH 9/28 ext4: extended attribute value size limit is enforced by vfs

In reply to Tahsin Erdogan

EXT4_XATTR_MAX_LARGE_EA_SIZE definition in ext4 is currently unused. Besides, vfs enforces its own 64k limit which makes the 1MB limit in ext4 redundant. Remove it.

---
 fs/ext4/ext4.h | 6 ------
 1 file changed, 6 deletions(-)
fs/ext4/ext4.h +0 -6
index 5d5fc0d0e2bc..2cdd6070e348 100644
@@ -2221,12 +2221,6 @@ struct mmpd_data {
 #define EXT4_MMP_MAX_CHECK_INTERVAL	300UL
 
 /*
- * Maximum size of xattr attributes for FEATURE_INCOMPAT_EA_INODE 1Mb
- * This limit is arbitrary, but is reasonable for the xattr API.
- */
-#define EXT4_XATTR_MAX_LARGE_EA_SIZE    (1024 * 1024)
-
-/*
  * Function prototypes
  */
 
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#12 lore raw

Re: [PATCH 09/28] ext4: extended attribute value size limit is enforced by vfs

Quoted 14 lines · Tahsin Erdogan

EXT4_XATTR_MAX_LARGE_EA_SIZE definition in ext4 is currently unused. Besides, vfs enforces its own 64k limit which makes the 1MB limit in ext4 redundant. Remove it.

---
 fs/ext4/ext4.h | 6 ------
 1 file changed, 6 deletions(-)
fs/ext4/ext4.h +0 -0
index 5d5fc0d0e2bc..2cdd6070e348 100644

fs/ext4/ext4.h struct mmpd_data { · line 2227

Quoted 7 lines
fs/ext4/ext4.h +0 -4
@@ -2221,12 +2221,6 @@ struct mmpd_data {
 #define EXT4_MMP_MAX_CHECK_INTERVAL	300UL
 
 /*
- * Maximum size of xattr attributes for FEATURE_INCOMPAT_EA_INODE 1Mb
- * This limit is arbitrary, but is reasonable for the xattr API.
- */
-#define EXT4_XATTR_MAX_LARGE_EA_SIZE    (1024 * 1024)

Uhhh... didn't you add this in patch 1/28? There's little point in adding a symbol just to delete it shortly thereafter.

--D

Quoted 8 lines
fs/ext4/ext4.h +0 -2
-
-/*
  * Function prototypes
  */
 
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#13 lore raw

Re: [PATCH 09/28] ext4: extended attribute value size limit is enforced by vfs

Hi Darrick,

Quoted 5 lines
Quoted 1 line

-#define EXT4_XATTR_MAX_LARGE_EA_SIZE (1024 * 1024)

Uhhh... didn't you add this in patch 1/28? There's little point in adding a symbol just to delete it shortly thereafter.

1/28 is the original patch I've received from Andreas. I wanted to leave his patch in its original form as much as possible so that the modifications I made on them are clear. If preferred, I can squash them later, but I thought it is a little clearer this way.

#14 lore raw

PATCH 10/28 ext4: change ext4_xattr_inode_iget() signature

In reply to Tahsin Erdogan

In general, kernel functions indicate success/failure through their return values. This function returns the status as an output parameter and reserves the return value for the inode. Make it follow the general convention.

---
 fs/ext4/xattr.c | 73 +++++++++++++++++++++++++++++++--------------------------
 fs/ext4/xattr.h |  2 --
 2 files changed, 40 insertions(+), 35 deletions(-)
fs/ext4/xattr.c +40 -33
index 13daf634244b..d9477d01be9b 100644
@@ -312,40 +312,47 @@ ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t *size)
 	return 0;
 }
 
-struct inode *ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino, int *err)
+static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
+				 struct inode **ea_inode)
 {
-	struct inode *ea_inode = NULL;
+	struct inode *inode;
+	int err;
+
+	inode = ext4_iget(parent->i_sb, ea_ino);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		ext4_error(parent->i_sb, "error while reading EA inode %lu "
+			   "err=%d", ea_ino, err);
+		return err;
+	}
 
-	ea_inode = ext4_iget(parent->i_sb, ea_ino);
-	if (IS_ERR(ea_inode) || is_bad_inode(ea_inode)) {
-		int rc = IS_ERR(ea_inode) ? PTR_ERR(ea_inode) : 0;
+	if (is_bad_inode(inode)) {
 		ext4_error(parent->i_sb, "error while reading EA inode %lu "
-			   "/ %d %d", ea_ino, rc, is_bad_inode(ea_inode));
-		*err = rc != 0 ? rc : -EIO;
-		return NULL;
+			   "is_bad_inode", ea_ino);
+		err = -EIO;
+		goto error;
 	}
 
-	if (EXT4_XATTR_INODE_GET_PARENT(ea_inode) != parent->i_ino ||
-	    ea_inode->i_generation != parent->i_generation) {
+	if (EXT4_XATTR_INODE_GET_PARENT(inode) != parent->i_ino ||
+	    inode->i_generation != parent->i_generation) {
 		ext4_error(parent->i_sb, "Backpointer from EA inode %lu "
-			   "to parent invalid.", ea_ino);
-		*err = -EINVAL;
+			   "to parent is invalid.", ea_ino);
+		err = -EINVAL;
 		goto error;
 	}
 
-	if (!(EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL)) {
+	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 		ext4_error(parent->i_sb, "EA inode %lu does not have "
 			   "EXT4_EA_INODE_FL flag set.\n", ea_ino);
-		*err = -EINVAL;
+		err = -EINVAL;
 		goto error;
 	}
 
-	*err = 0;
-	return ea_inode;
-
+	*ea_inode = inode;
+	return 0;
 error:
-	iput(ea_inode);
-	return NULL;
+	iput(inode);
+	return err;
 }
 
 /*
@@ -355,17 +362,17 @@ static int
 ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
 		     size_t *size)
 {
-	struct inode *ea_inode = NULL;
-	int err;
+	struct inode *ea_inode;
+	int ret;
 
-	ea_inode = ext4_xattr_inode_iget(inode, ea_ino, &err);
-	if (err)
-		return err;
+	ret = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+	if (ret)
+		return ret;
 
-	err = ext4_xattr_inode_read(ea_inode, buffer, size);
+	ret = ext4_xattr_inode_read(ea_inode, buffer, size);
 	iput(ea_inode);
 
-	return err;
+	return ret;
 }
 
 static int
@@ -868,7 +875,7 @@ int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino)
 	struct inode *ea_inode = NULL;
 	int err;
 
-	ea_inode = ext4_xattr_inode_iget(inode, ea_ino, &err);
+	err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
 	if (err)
 		return err;
 
@@ -1948,7 +1955,7 @@ static int
 ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode,
 			int credits, struct ext4_xattr_ino_array *lea_ino_array)
 {
-	struct inode *ea_inode = NULL;
+	struct inode *ea_inode;
 	int idx = 0, error = 0;
 
 	if (lea_ino_array == NULL)
@@ -1967,8 +1974,8 @@ ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode,
 				return error;
 			}
 		}
-		ea_inode = ext4_xattr_inode_iget(inode,
-				lea_ino_array->xia_inodes[idx], &error);
+		error = ext4_xattr_inode_iget(inode,
+				lea_ino_array->xia_inodes[idx], &ea_inode);
 		if (error)
 			continue;
 		inode_lock(ea_inode);
@@ -2085,7 +2092,7 @@ void
 ext4_xattr_inode_array_free(struct inode *inode,
 			    struct ext4_xattr_ino_array *lea_ino_array)
 {
-	struct inode	*ea_inode = NULL;
+	struct inode	*ea_inode;
 	int		idx = 0;
 	int		err;
 
@@ -2093,8 +2100,8 @@ ext4_xattr_inode_array_free(struct inode *inode,
 		return;
 
 	for (; idx < lea_ino_array->xia_count; ++idx) {
-		ea_inode = ext4_xattr_inode_iget(inode,
-				lea_ino_array->xia_inodes[idx], &err);
+		err = ext4_xattr_inode_iget(inode,
+				lea_ino_array->xia_inodes[idx], &ea_inode);
 		if (err)
 			continue;
 		/* for inode's i_count get from ext4_xattr_delete_inode */
fs/ext4/xattr.h +0 -2
index e8bef79bdc38..b6ef99d1a061 100644
@@ -161,8 +161,6 @@ extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
 
-extern struct inode *ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
-					   int *err);
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_ino_array **array);
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#15 lore raw

PATCH 11/28 ext4: clean up ext4_xattr_inode_get()

In reply to Tahsin Erdogan

The input and output values of *size parameter are equal on successful return from ext4_xattr_inode_get(). On error return, the callers ignore the output value so there is no need to update it.

Also check for NULL return from ext4_bread(). If the actual xattr inode size happens to be smaller than the expected size, ext4_bread() may return NULL which would indicate data corruption.

---
 fs/ext4/xattr.c | 35 +++++++++++++----------------------
 1 file changed, 13 insertions(+), 22 deletions(-)
fs/ext4/xattr.c +13 -22
index d9477d01be9b..8e855fc2eb03 100644
@@ -278,37 +278,28 @@ ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 /*
  * Read the EA value from an inode.
  */
-static int
-ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t *size)
+static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 {
 	unsigned long block = 0;
 	struct buffer_head *bh = NULL;
-	int blocksize;
-	size_t csize, ret_size = 0;
-
-	if (*size == 0)
-		return 0;
+	int blocksize = ea_inode->i_sb->s_blocksize;
+	size_t csize, copied = 0;
 
-	blocksize = ea_inode->i_sb->s_blocksize;
-
-	while (ret_size < *size) {
-		csize = (*size - ret_size) > blocksize ? blocksize :
-							*size - ret_size;
+	while (copied < size) {
+		csize = (size - copied) > blocksize ? blocksize : size - copied;
 		bh = ext4_bread(NULL, ea_inode, block, 0);
-		if (IS_ERR(bh)) {
-			*size = ret_size;
+		if (IS_ERR(bh))
 			return PTR_ERR(bh);
-		}
+		if (!bh)
+			return -EFSCORRUPTED;
+
 		memcpy(buf, bh->b_data, csize);
 		brelse(bh);
 
 		buf += csize;
 		block += 1;
-		ret_size += csize;
+		copied += csize;
 	}
-
-	*size = ret_size;
-
 	return 0;
 }
 
@@ -360,7 +351,7 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
  */
 static int
 ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
-		     size_t *size)
+		     size_t size)
 {
 	struct inode *ea_inode;
 	int ret;
@@ -417,7 +408,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 		if (entry->e_value_inum) {
 			error = ext4_xattr_inode_get(inode,
 					     le32_to_cpu(entry->e_value_inum),
-					     buffer, &size);
+					     buffer, size);
 			if (error)
 				goto cleanup;
 		} else {
@@ -467,7 +458,7 @@ ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
 		if (entry->e_value_inum) {
 			error = ext4_xattr_inode_get(inode,
 					     le32_to_cpu(entry->e_value_inum),
-					     buffer, &size);
+					     buffer, size);
 			if (error)
 				goto cleanup;
 		} else {
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#16 lore raw

PATCH 12/28 ext4: add missing le32_to_cpu(e_value_inum) conversions

In reply to Tahsin Erdogan

Two places in code missed converting xattr inode number using le32_to_cpu().

---
 fs/ext4/xattr.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)
fs/ext4/xattr.c +5 -4
index 8e855fc2eb03..4dd8be16d175 100644
@@ -1997,6 +1997,7 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 	struct ext4_inode *raw_inode;
 	struct ext4_iloc iloc;
 	struct ext4_xattr_entry *entry;
+	unsigned int ea_ino;
 	int credits = 3, error = 0;
 
 	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
@@ -2011,8 +2012,8 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 	     entry = EXT4_XATTR_NEXT(entry)) {
 		if (!entry->e_value_inum)
 			continue;
-		if (ext4_expand_ino_array(lea_ino_array,
-					  entry->e_value_inum) != 0) {
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		if (ext4_expand_ino_array(lea_ino_array, ea_ino) != 0) {
 			brelse(iloc.bh);
 			goto cleanup;
 		}
@@ -2044,8 +2045,8 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 	     entry = EXT4_XATTR_NEXT(entry)) {
 		if (!entry->e_value_inum)
 			continue;
-		if (ext4_expand_ino_array(lea_ino_array,
-					  entry->e_value_inum) != 0)
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		if (ext4_expand_ino_array(lea_ino_array, ea_ino) != 0)
 			goto cleanup;
 		entry->e_value_inum = 0;
 	}
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#17 lore raw

PATCH 13/28 ext4: ext4_xattr_value_same() should return false for external data

In reply to Tahsin Erdogan

ext4_xattr_value_same() is used as a quick optimization in case the new xattr value is identical to the previous value. When xattr value is stored in a xattr inode the check becomes expensive so it is better to just assume that they are not equal.

---
 fs/ext4/xattr.c | 3 +++
 1 file changed, 3 insertions(+)
fs/ext4/xattr.c +3 -0
index 4dd8be16d175..681a9b5eefd8 100644
@@ -1428,6 +1428,9 @@ static int ext4_xattr_value_same(struct ext4_xattr_search *s,
 {
 	void *value;
 
+	/* When e_value_inum is set the value is stored externally. */
+	if (s->here->e_value_inum)
+		return 0;
 	if (le32_to_cpu(s->here->e_value_size) != i->value_len)
 		return 0;
 	value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs);
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#18 lore raw

PATCH 14/28 ext4: fix ext4_xattr_make_inode_space() value size calculation

In reply to Tahsin Erdogan

ext4_xattr_make_inode_space() is interested in calculating the inline space used in an inode. When a xattr entry refers to an external inode the value size indicates the external inode size, not the value size in the inline area. Change the function to take this into account.

---
 fs/ext4/xattr.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)
fs/ext4/xattr.c +8 -5
index 681a9b5eefd8..6a6bee246873 100644
@@ -1747,9 +1747,10 @@ static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
 		last = IFIRST(header);
 		/* Find the entry best suited to be pushed into EA block */
 		for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
-			total_size =
-			EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
-					EXT4_XATTR_LEN(last->e_name_len);
+			total_size = EXT4_XATTR_LEN(last->e_name_len);
+			if (!last->e_value_inum)
+				total_size += EXT4_XATTR_SIZE(
+					       le32_to_cpu(last->e_value_size));
 			if (total_size <= bfree &&
 			    total_size < min_total_size) {
 				if (total_size + ifree < isize_diff) {
@@ -1768,8 +1769,10 @@ static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode,
 		}
 
 		entry_size = EXT4_XATTR_LEN(entry->e_name_len);
-		total_size = entry_size +
-			EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size));
+		total_size = entry_size;
+		if (!entry->e_value_inum)
+			total_size += EXT4_XATTR_SIZE(
+					      le32_to_cpu(entry->e_value_size));
 		error = ext4_xattr_move_to_block(handle, inode, raw_inode,
 						 entry);
 		if (error)
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#19 lore raw

PATCH 15/28 ext4: fix ext4_xattr_move_to_block()

In reply to Tahsin Erdogan

When moving xattr entries from inline area to a xattr block, entries that refer to external xattr inodes need special handling because value data is not available in the inline area but rather should be read from its external inode.

---
 fs/ext4/xattr.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)
fs/ext4/xattr.c +13 -6
index 6a6bee246873..9c243b3510b7 100644
@@ -1658,18 +1658,16 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
 	struct ext4_xattr_ibody_find *is = NULL;
 	struct ext4_xattr_block_find *bs = NULL;
 	char *buffer = NULL, *b_entry_name = NULL;
-	size_t value_offs, value_size;
+	size_t value_size = le32_to_cpu(entry->e_value_size);
 	struct ext4_xattr_info i = {
 		.value = NULL,
 		.value_len = 0,
 		.name_index = entry->e_name_index,
+		.in_inode = !!entry->e_value_inum,
 	};
 	struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
 	int error;
 
-	value_offs = le16_to_cpu(entry->e_value_offs);
-	value_size = le32_to_cpu(entry->e_value_size);
-
 	is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
 	bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS);
 	buffer = kmalloc(value_size, GFP_NOFS);
@@ -1685,7 +1683,17 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
 	bs->bh = NULL;
 
 	/* Save the entry name and the entry value */
-	memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
+	if (entry->e_value_inum) {
+		error = ext4_xattr_inode_get(inode,
+					     le32_to_cpu(entry->e_value_inum),
+					     buffer, value_size);
+		if (error)
+			goto out;
+	} else {
+		size_t value_offs = le16_to_cpu(entry->e_value_offs);
+		memcpy(buffer, (void *)IFIRST(header) + value_offs, value_size);
+	}
+
 	memcpy(b_entry_name, entry->e_name, entry->e_name_len);
 	b_entry_name[entry->e_name_len] = '\0';
 	i.name = b_entry_name;
@@ -1703,7 +1711,6 @@ static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode,
 	if (error)
 		goto out;
 
-	i.name = b_entry_name;
 	i.value = buffer;
 	i.value_len = value_size;
 	error = ext4_xattr_block_find(inode, &i, bs);
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#20 lore raw

PATCH 16/28 ext4: fix ext4_xattr_cmp()

In reply to Tahsin Erdogan

When a xattr entry refers to an external inode, the value data is not available in the inline area so we should not attempt to read it using value offset.

---
 fs/ext4/xattr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
fs/ext4/xattr.c +2 -1
index 9c243b3510b7..739f73a5a345 100644
@@ -2169,7 +2169,8 @@ ext4_xattr_cmp(struct ext4_xattr_header *header1,
 		    entry1->e_value_inum != entry2->e_value_inum ||
 		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
 			return 1;
-		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
+		if (!entry1->e_value_inum &&
+		    memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
 			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
 			   le32_to_cpu(entry1->e_value_size)))
 			return 1;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#21 lore raw

PATCH 17/28 ext4: fix credits calculation for xattr inode

In reply to Tahsin Erdogan

When there is no space for a value in xattr block, it may be stored in an xattr inode even if the value length is less than EXT4_XATTR_MIN_LARGE_EA_SIZE(). So the current assumption in credits calculation is wrong.

---
 fs/ext4/xattr.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
fs/ext4/xattr.c +1 -2
index 739f73a5a345..dcf7ec98f138 100644
@@ -1590,8 +1590,7 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 	if (error)
 		return error;
 
-	if ((value_len >= EXT4_XATTR_MIN_LARGE_EA_SIZE(sb->s_blocksize)) &&
-	    ext4_has_feature_ea_inode(sb)) {
+	if (ext4_has_feature_ea_inode(sb)) {
 		int nrblocks = (value_len + sb->s_blocksize - 1) >>
 					sb->s_blocksize_bits;
 
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#22 lore raw

PATCH 18/28 ext4: retry storing value in external inode with xattr block too

In reply to Tahsin Erdogan

When value size is <= EXT4_XATTR_MIN_LARGE_EA_SIZE(), and it doesn't fit in either inline or xattr block, a second try is made to store it in an external inode while storing the entry itself in inline area. There should also be an attempt to store the entry in xattr block.

This patch adds a retry loop to do that. It also makes the caller the sole decider on whether to store a value in an external inode.

---
 fs/ext4/xattr.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)
fs/ext4/xattr.c +18 -17
index dcf7ec98f138..1d354e447842 100644
@@ -911,11 +911,6 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 	int in_inode = i->in_inode;
 	int rc;
 
-	if (ext4_has_feature_ea_inode(inode->i_sb) &&
-	    (EXT4_XATTR_SIZE(i->value_len) >
-	     EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
-		in_inode = 1;
-
 	/* Compute min_offs and last. */
 	last = s->first;
 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
@@ -1097,7 +1092,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 {
 	struct super_block *sb = inode->i_sb;
 	struct buffer_head *new_bh = NULL;
-	struct ext4_xattr_search *s = &bs->s;
+	struct ext4_xattr_search s_copy = bs->s;
+	struct ext4_xattr_search *s = &s_copy;
 	struct mb_cache_entry *ce = NULL;
 	int error = 0;
 	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
@@ -1519,6 +1515,11 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
 			goto cleanup;
 
+		if (ext4_has_feature_ea_inode(inode->i_sb) &&
+		    (EXT4_XATTR_SIZE(i.value_len) >
+			EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
+			i.in_inode = 1;
+	retry_inode:
 		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
 		if (!error && !bs.s.not_found) {
 			i.value = NULL;
@@ -1530,20 +1531,20 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 					goto cleanup;
 			}
 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
-			if (ext4_has_feature_ea_inode(inode->i_sb) &&
-			    error == -ENOSPC) {
-				/* xattr not fit to block, store at external
-				 * inode */
-				i.in_inode = 1;
-				error = ext4_xattr_ibody_set(handle, inode,
-							     &i, &is);
-			}
-			if (error)
-				goto cleanup;
-			if (!is.s.not_found) {
+			if (!error && !is.s.not_found) {
 				i.value = NULL;
 				error = ext4_xattr_ibody_set(handle, inode, &i,
 							     &is);
+			} else if (error == -ENOSPC) {
+				/*
+				 * Xattr does not fit in the block, store at
+				 * external inode if possible.
+				 */
+				if (ext4_has_feature_ea_inode(inode->i_sb) &&
+				    !i.in_inode) {
+					i.in_inode = 1;
+					goto retry_inode;
+				}
 			}
 		}
 	}
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#23 lore raw

PATCH v2 18/31 ext4: retry storing value in external inode with xattr block too

When value size is <= EXT4_XATTR_MIN_LARGE_EA_SIZE(), and it doesn't fit in either inline or xattr block, a second try is made to store it in an external inode while storing the entry itself in inline area. There should also be an attempt to store the entry in xattr block.

This patch adds a retry loop to do that. It also makes the caller the sole decider on whether to store a value in an external inode.

---
v2: fix checkpatch.pl warning about indented retry_inode: label

 fs/ext4/xattr.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)
fs/ext4/xattr.c +18 -17
index dcf7ec98f138..0dfae3f8e209 100644
@@ -911,11 +911,6 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 	int in_inode = i->in_inode;
 	int rc;
 
-	if (ext4_has_feature_ea_inode(inode->i_sb) &&
-	    (EXT4_XATTR_SIZE(i->value_len) >
-	     EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
-		in_inode = 1;
-
 	/* Compute min_offs and last. */
 	last = s->first;
 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
@@ -1097,7 +1092,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 {
 	struct super_block *sb = inode->i_sb;
 	struct buffer_head *new_bh = NULL;
-	struct ext4_xattr_search *s = &bs->s;
+	struct ext4_xattr_search s_copy = bs->s;
+	struct ext4_xattr_search *s = &s_copy;
 	struct mb_cache_entry *ce = NULL;
 	int error = 0;
 	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
@@ -1519,6 +1515,11 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 		if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i))
 			goto cleanup;
 
+		if (ext4_has_feature_ea_inode(inode->i_sb) &&
+		    (EXT4_XATTR_SIZE(i.value_len) >
+			EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize)))
+			i.in_inode = 1;
+retry_inode:
 		error = ext4_xattr_ibody_set(handle, inode, &i, &is);
 		if (!error && !bs.s.not_found) {
 			i.value = NULL;
@@ -1530,20 +1531,20 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 					goto cleanup;
 			}
 			error = ext4_xattr_block_set(handle, inode, &i, &bs);
-			if (ext4_has_feature_ea_inode(inode->i_sb) &&
-			    error == -ENOSPC) {
-				/* xattr not fit to block, store at external
-				 * inode */
-				i.in_inode = 1;
-				error = ext4_xattr_ibody_set(handle, inode,
-							     &i, &is);
-			}
-			if (error)
-				goto cleanup;
-			if (!is.s.not_found) {
+			if (!error && !is.s.not_found) {
 				i.value = NULL;
 				error = ext4_xattr_ibody_set(handle, inode, &i,
 							     &is);
+			} else if (error == -ENOSPC) {
+				/*
+				 * Xattr does not fit in the block, store at
+				 * external inode if possible.
+				 */
+				if (ext4_has_feature_ea_inode(inode->i_sb) &&
+				    !i.in_inode) {
+					i.in_inode = 1;
+					goto retry_inode;
+				}
 			}
 		}
 	}
Signature · 1 line
2.13.1.518.g3df882009-goog
#24 lore raw

PATCH 19/28 ext4: ext4_xattr_delete_inode() should return accurate errors

In reply to Tahsin Erdogan

In a few places the function returns without trying to pass the actual error code to the caller. Fix those.

---
 fs/ext4/xattr.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)
fs/ext4/xattr.c +10 -6
index 1d354e447842..230e0aa76777 100644
@@ -2026,7 +2026,8 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 		if (!entry->e_value_inum)
 			continue;
 		ea_ino = le32_to_cpu(entry->e_value_inum);
-		if (ext4_expand_ino_array(lea_ino_array, ea_ino) != 0) {
+		error = ext4_expand_ino_array(lea_ino_array, ea_ino);
+		if (error) {
 			brelse(iloc.bh);
 			goto cleanup;
 		}
@@ -2037,20 +2038,22 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 delete_external_ea:
 	if (!EXT4_I(inode)->i_file_acl) {
 		/* add xattr inode to orphan list */
-		ext4_xattr_inode_orphan_add(handle, inode, credits,
-						*lea_ino_array);
+		error = ext4_xattr_inode_orphan_add(handle, inode, credits,
+						    *lea_ino_array);
 		goto cleanup;
 	}
 	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
 	if (!bh) {
 		EXT4_ERROR_INODE(inode, "block %llu read error",
 				 EXT4_I(inode)->i_file_acl);
+		error = -EIO;
 		goto cleanup;
 	}
 	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
 	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
 		EXT4_ERROR_INODE(inode, "bad block %llu",
 				 EXT4_I(inode)->i_file_acl);
+		error = -EFSCORRUPTED;
 		goto cleanup;
 	}
 
@@ -2059,7 +2062,8 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 		if (!entry->e_value_inum)
 			continue;
 		ea_ino = le32_to_cpu(entry->e_value_inum);
-		if (ext4_expand_ino_array(lea_ino_array, ea_ino) != 0)
+		error = ext4_expand_ino_array(lea_ino_array, ea_ino);
+		if (error)
 			goto cleanup;
 		entry->e_value_inum = 0;
 	}
@@ -2067,7 +2071,7 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 	/* add xattr inode to orphan list */
 	error = ext4_xattr_inode_orphan_add(handle, inode, credits,
 					*lea_ino_array);
-	if (error != 0)
+	if (error)
 		goto cleanup;
 
 	if (!IS_NOQUOTA(inode))
@@ -2077,7 +2081,7 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 		error = ext4_journal_extend(handle, credits);
 		if (error > 0)
 			error = ext4_journal_restart(handle, credits);
-		if (error != 0) {
+		if (error) {
 			ext4_warning(inode->i_sb,
 				"couldn't extend journal (err %d)", error);
 			goto cleanup;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#25 lore raw

PATCH 20/28 ext4: improve journal credit handling in set xattr paths

In reply to Tahsin Erdogan

Both ext4_set_acl() and ext4_set_context() need to be made aware of ea_inode feature when it comes to credits calculation.

Also add a sufficient credits check in ext4_xattr_set_handle() right after xattr write lock is grabbed. Original credits calculation is done outside the lock so there is a possiblity that the initially calculated credits are not sufficient anymore.

---
 fs/ext4/acl.c       |  7 ++++---
 fs/ext4/ext4_jbd2.h | 14 --------------
 fs/ext4/super.c     |  6 +++---
 fs/ext4/xattr.c     | 55 +++++++++++++++++++++++++++++++++++++++++------------
 fs/ext4/xattr.h     |  1 +
 5 files changed, 51 insertions(+), 32 deletions(-)
fs/ext4/acl.c +4 -3
index 3ec0e46de95f..74f7ac539e00 100644
@@ -231,14 +231,15 @@ int
 ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
 	handle_t *handle;
-	int error, retries = 0;
+	int error, credits, retries = 0;
+	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
 
 	error = dquot_initialize(inode);
 	if (error)
 		return error;
 retry:
-	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
-				    ext4_jbd2_credits_xattr(inode));
+	credits = ext4_xattr_set_credits(inode, acl_size);
+	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
fs/ext4/ext4_jbd2.h +0 -14
index f97611171023..a5bda70feed5 100644
@@ -104,20 +104,6 @@
 #define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
 #define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
 
-static inline int ext4_jbd2_credits_xattr(struct inode *inode)
-{
-	int credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
-
-	/*
-	 * In case of inline data, we may push out the data to a block,
-	 * so we need to reserve credits for this eventuality
-	 */
-	if (ext4_has_inline_data(inode))
-		credits += ext4_writepage_trans_blocks(inode) + 1;
-	return credits;
-}
-
-
 /*
  * Ext4 handle operation types -- for logging purposes
  */
fs/ext4/super.c +3 -3
index d37c81f327e7..b02a23ec92ca 100644
@@ -1143,7 +1143,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 							void *fs_data)
 {
 	handle_t *handle = fs_data;
-	int res, res2, retries = 0;
+	int res, res2, credits, retries = 0;
 
 	res = ext4_convert_inline_data(inode);
 	if (res)
@@ -1178,8 +1178,8 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	handle = ext4_journal_start(inode, EXT4_HT_MISC,
-			ext4_jbd2_credits_xattr(inode));
+	credits = ext4_xattr_set_credits(inode, len);
+	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
fs/ext4/xattr.c +43 -12

79 lines not on this page · raw message

fs/ext4/xattr.h +1 -0
index b6ef99d1a061..e82c5fe36a26 100644
@@ -160,6 +160,7 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#26 lore raw

PATCH v2 20/31 ext4: improve journal credit handling in set xattr paths

Both ext4_set_acl() and ext4_set_context() need to be made aware of ea_inode feature when it comes to credits calculation.

Also add a sufficient credits check in ext4_xattr_set_handle() right after xattr write lock is grabbed. Original credits calculation is done outside the lock so there is a possiblity that the initially calculated credits are not sufficient anymore.

---
v2: fixed checkpatch.pl warning about replacing spaces with tab

 fs/ext4/acl.c       |  7 ++++---
 fs/ext4/ext4_jbd2.h | 14 --------------
 fs/ext4/super.c     |  6 +++---
 fs/ext4/xattr.c     | 55 +++++++++++++++++++++++++++++++++++++++++------------
 fs/ext4/xattr.h     |  1 +
 5 files changed, 51 insertions(+), 32 deletions(-)
fs/ext4/acl.c +4 -3
index 3ec0e46de95f..74f7ac539e00 100644
@@ -231,14 +231,15 @@ int
 ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 {
 	handle_t *handle;
-	int error, retries = 0;
+	int error, credits, retries = 0;
+	size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
 
 	error = dquot_initialize(inode);
 	if (error)
 		return error;
 retry:
-	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
-				    ext4_jbd2_credits_xattr(inode));
+	credits = ext4_xattr_set_credits(inode, acl_size);
+	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
fs/ext4/ext4_jbd2.h +0 -14
index f97611171023..a5bda70feed5 100644
@@ -104,20 +104,6 @@
 #define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
 #define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
 
-static inline int ext4_jbd2_credits_xattr(struct inode *inode)
-{
-	int credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
-
-	/*
-	 * In case of inline data, we may push out the data to a block,
-	 * so we need to reserve credits for this eventuality
-	 */
-	if (ext4_has_inline_data(inode))
-		credits += ext4_writepage_trans_blocks(inode) + 1;
-	return credits;
-}
-
-
 /*
  * Ext4 handle operation types -- for logging purposes
  */
fs/ext4/super.c +3 -3
index d37c81f327e7..b02a23ec92ca 100644
@@ -1143,7 +1143,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 							void *fs_data)
 {
 	handle_t *handle = fs_data;
-	int res, res2, retries = 0;
+	int res, res2, credits, retries = 0;
 
 	res = ext4_convert_inline_data(inode);
 	if (res)
@@ -1178,8 +1178,8 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	handle = ext4_journal_start(inode, EXT4_HT_MISC,
-			ext4_jbd2_credits_xattr(inode));
+	credits = ext4_xattr_set_credits(inode, len);
+	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
 
fs/ext4/xattr.c +43 -12

79 lines not on this page · raw message

fs/ext4/xattr.h +1 -0
index b6ef99d1a061..e82c5fe36a26 100644
@@ -160,6 +160,7 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
Signature · 1 line
2.13.1.518.g3df882009-goog
#27 lore raw

PATCH 21/28 ext4: modify ext4_xattr_ino_array to hold struct inode *

In reply to Tahsin Erdogan

Tracking struct inode * rather than the inode number eliminates the repeated ext4_xattr_inode_iget() call later. The second call cannot fail in practice but still requires explanation when it wants to ignore the return value. Avoid the trouble and make things simple.

---
 fs/ext4/ext4.h  |  6 ++--
 fs/ext4/inode.c |  8 ++---
 fs/ext4/xattr.c | 93 ++++++++++++++++++++++++++++-----------------------------
 fs/ext4/xattr.h |  5 ++--
 4 files changed, 53 insertions(+), 59 deletions(-)
fs/ext4/ext4.h +3 -3
index 2cdd6070e348..603edb5ff304 100644
@@ -2232,9 +2232,9 @@ struct mmpd_data {
 # define ATTRIB_NORET	__attribute__((noreturn))
 # define NORET_AND	noreturn,
 
-struct ext4_xattr_ino_array {
-	unsigned int xia_count;		/* # of used item in the array */
-	unsigned int xia_inodes[0];
+struct ext4_xattr_inode_array {
+	unsigned int count;		/* # of used items in the array */
+	struct inode *inodes[0];
 };
 /* bitmap.c */
 extern unsigned int ext4_count_free(char *bitmap, unsigned numchars);
fs/ext4/inode.c +3 -5
index d095bf7ad390..8ee20b586567 100644
@@ -188,7 +188,7 @@ void ext4_evict_inode(struct inode *inode)
 	handle_t *handle;
 	int err;
 	int extra_credits = 3;
-	struct ext4_xattr_ino_array *lea_ino_array = NULL;
+	struct ext4_xattr_inode_array *ea_inode_array = NULL;
 
 	trace_ext4_evict_inode(inode);
 
@@ -257,7 +257,7 @@ void ext4_evict_inode(struct inode *inode)
 	/*
 	 * Delete xattr inode before deleting the main inode.
 	 */
-	err = ext4_xattr_delete_inode(handle, inode, &lea_ino_array);
+	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
 	if (err) {
 		ext4_warning(inode->i_sb,
 			     "couldn't delete inode's xattr (err %d)", err);
@@ -345,9 +345,7 @@ void ext4_evict_inode(struct inode *inode)
 
 	ext4_journal_stop(handle);
 	sb_end_intwrite(inode->i_sb);
-
-	if (lea_ino_array != NULL)
-		ext4_xattr_inode_array_free(inode, lea_ino_array);
+	ext4_xattr_inode_array_free(ea_inode_array);
 	return;
 no_delete:
 	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
fs/ext4/xattr.c +45 -48

185 lines not on this page · raw message

fs/ext4/xattr.h +2 -3
index e82c5fe36a26..323eba54f72f 100644
@@ -164,9 +164,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-				   struct ext4_xattr_ino_array **array);
-extern void ext4_xattr_inode_array_free(struct inode *inode,
-					struct ext4_xattr_ino_array *array);
+				   struct ext4_xattr_inode_array **array);
+extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 			    struct ext4_inode *raw_inode, handle_t *handle);
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#28 lore raw

PATCH 22/28 ext4: move struct ext4_xattr_inode_array to xattr.h

In reply to Tahsin Erdogan

Since this is a xattr specific data structure it is cleaner to keep it in xattr header file.

---
 fs/ext4/ext4.h  | 4 ----
 fs/ext4/xattr.h | 5 +++++
 2 files changed, 5 insertions(+), 4 deletions(-)
fs/ext4/ext4.h +0 -4
index 603edb5ff304..580fdb753f29 100644
@@ -2232,10 +2232,6 @@ struct mmpd_data {
 # define ATTRIB_NORET	__attribute__((noreturn))
 # define NORET_AND	noreturn,
 
-struct ext4_xattr_inode_array {
-	unsigned int count;		/* # of used items in the array */
-	struct inode *inodes[0];
-};
 /* bitmap.c */
 extern unsigned int ext4_count_free(char *bitmap, unsigned numchars);
 void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
fs/ext4/xattr.h +5 -0
index 323eba54f72f..adf761518a73 100644
@@ -117,6 +117,11 @@ struct ext4_xattr_ibody_find {
 	struct ext4_iloc iloc;
 };
 
+struct ext4_xattr_inode_array {
+	unsigned int count;		/* # of used items in the array */
+	struct inode *inodes[0];
+};
+
 extern const struct xattr_handler ext4_xattr_user_handler;
 extern const struct xattr_handler ext4_xattr_trusted_handler;
 extern const struct xattr_handler ext4_xattr_security_handler;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#29 lore raw

PATCH 23/28 mbcache: make mbcache more generic

In reply to Tahsin Erdogan

Large xattr feature would like to use the mbcache for xattr value deduplication. Current implementation is geared towards xattr block deduplication. Make it more generic so that it can be used by both.

---
 fs/ext2/xattr.c         | 18 +++++++++---------
 fs/ext4/xattr.c         | 10 +++++-----
 fs/mbcache.c            | 43 +++++++++++++++++++++----------------------
 include/linux/mbcache.h | 14 ++++++++------
 4 files changed, 43 insertions(+), 42 deletions(-)
fs/ext2/xattr.c +9 -9
index fbdb8f171893..1e5f76070580 100644
@@ -493,8 +493,8 @@ bad_block:		ext2_error(sb, "ext2_xattr_set",
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect modified block
 			 */
-			mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache,
-						    hash, bh->b_blocknr);
+			mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash,
+					      bh->b_blocknr);
 
 			/* keep the buffer locked while modifying it. */
 		} else {
@@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect freed block
 			 */
-			mb_cache_entry_delete_block(ext2_mb_cache,
-						    hash, old_bh->b_blocknr);
+			mb_cache_entry_delete(ext2_mb_cache, hash,
+					      old_bh->b_blocknr);
 			/* Free the old block. */
 			ea_bdebug(old_bh, "freeing");
 			ext2_free_blocks(inode, old_bh->b_blocknr, 1);
@@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode)
 		 * This must happen under buffer lock for ext2_xattr_set2() to
 		 * reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache,
-					    hash, bh->b_blocknr);
+		mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash,
+				      bh->b_blocknr);
 		ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
 		get_bh(bh);
 		bforget(bh);
@@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			ext2_error(inode->i_sb, "ext2_xattr_cache_find",
 				"inode %ld: block %ld read error",
-				inode->i_ino, (unsigned long) ce->e_block);
+				inode->i_ino, (unsigned long) ce->e_value);
 		} else {
 			lock_buffer(bh);
 			/*
@@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 			} else if (le32_to_cpu(HDR(bh)->h_refcount) >
 				   EXT2_XATTR_REFCOUNT_MAX) {
 				ea_idebug(inode, "block %ld refcount %d>%d",
-					  (unsigned long) ce->e_block,
+					  (unsigned long) ce->e_value,
 					  le32_to_cpu(HDR(bh)->h_refcount),
 					  EXT2_XATTR_REFCOUNT_MAX);
 			} else if (!ext2_xattr_cmp(header, HDR(bh))) {
fs/ext4/xattr.c +5 -5
index 886d06e409b6..772948f168c3 100644
@@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		 * This must happen under buffer lock for
 		 * ext4_xattr_block_set() to reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
+		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
 		get_bh(bh);
 		unlock_buffer(bh);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
@@ -1115,8 +1115,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			 * ext4_xattr_block_set() to reliably detect modified
 			 * block
 			 */
-			mb_cache_entry_delete_block(ext4_mb_cache, hash,
-						    bs->bh->b_blocknr);
+			mb_cache_entry_delete(ext4_mb_cache, hash,
+					      bs->bh->b_blocknr);
 			ea_bdebug(bs->bh, "modifying in-place");
 			error = ext4_xattr_set_entry(i, s, handle, inode);
 			if (!error) {
@@ -2238,10 +2238,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			EXT4_ERROR_INODE(inode, "block %lu read error",
-					 (unsigned long) ce->e_block);
+					 (unsigned long) ce->e_value);
 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
 			*pce = ce;
 			return bh;
fs/mbcache.c +21 -22

104 lines not on this page · raw message

include/linux/mbcache.h +8 -6
index 86c9a8b480c5..e2d9f2f926a4 100644
@@ -9,6 +9,8 @@
 
 struct mb_cache;
 
+typedef sector_t cache_value_t;
+
 struct mb_cache_entry {
 	/* List of entries in cache - protected by cache->c_list_lock */
 	struct list_head	e_list;
@@ -19,15 +21,15 @@ struct mb_cache_entry {
 	u32			e_key;
 	u32			e_referenced:1;
 	u32			e_reusable:1;
-	/* Block number of hashed block - stable during lifetime of the entry */
-	sector_t		e_block;
+	/* User provided value - stable during lifetime of the entry */
+	cache_value_t		e_value;
 };
 
 struct mb_cache *mb_cache_create(int bucket_bits);
 void mb_cache_destroy(struct mb_cache *cache);
 
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable);
+			  cache_value_t value, bool reusable);
 void __mb_cache_entry_free(struct mb_cache_entry *entry);
 static inline int mb_cache_entry_put(struct mb_cache *cache,
 				     struct mb_cache_entry *entry)
@@ -38,10 +40,10 @@ static inline int mb_cache_entry_put(struct mb_cache *cache,
 	return 1;
 }
 
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				  sector_t block);
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key,
+			   cache_value_t value);
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block);
+					  cache_value_t value);
 struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
 						 u32 key);
 struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
Signature · 1 line
2.13.0.219.gdb65acc882-goog
reviewer
#30 lore raw

Re: [PATCH 23/28] mbcache: make mbcache more generic

Quoted 3 lines · Tahsin Erdogan

Large xattr feature would like to use the mbcache for xattr value deduplication. Current implementation is geared towards xattr block deduplication. Make it more generic so that it can be used by both.

Can you explain a bit more what do you mean by "make it more generic" as it seems you just rename a couple of things here...

Honza

Quoted 272 lines
---
 fs/ext2/xattr.c         | 18 +++++++++---------
 fs/ext4/xattr.c         | 10 +++++-----
 fs/mbcache.c            | 43 +++++++++++++++++++++----------------------
 include/linux/mbcache.h | 14 ++++++++------
 4 files changed, 43 insertions(+), 42 deletions(-)
fs/ext2/xattr.c +9 -9
index fbdb8f171893..1e5f76070580 100644
@@ -493,8 +493,8 @@ bad_block:		ext2_error(sb, "ext2_xattr_set",
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect modified block
 			 */
-			mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache,
-						    hash, bh->b_blocknr);
+			mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash,
+					      bh->b_blocknr);
 
 			/* keep the buffer locked while modifying it. */
 		} else {
@@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect freed block
 			 */
-			mb_cache_entry_delete_block(ext2_mb_cache,
-						    hash, old_bh->b_blocknr);
+			mb_cache_entry_delete(ext2_mb_cache, hash,
+					      old_bh->b_blocknr);
 			/* Free the old block. */
 			ea_bdebug(old_bh, "freeing");
 			ext2_free_blocks(inode, old_bh->b_blocknr, 1);
@@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode)
 		 * This must happen under buffer lock for ext2_xattr_set2() to
 		 * reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache,
-					    hash, bh->b_blocknr);
+		mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash,
+				      bh->b_blocknr);
 		ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
 		get_bh(bh);
 		bforget(bh);
@@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			ext2_error(inode->i_sb, "ext2_xattr_cache_find",
 				"inode %ld: block %ld read error",
-				inode->i_ino, (unsigned long) ce->e_block);
+				inode->i_ino, (unsigned long) ce->e_value);
 		} else {
 			lock_buffer(bh);
 			/*
@@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 			} else if (le32_to_cpu(HDR(bh)->h_refcount) >
 				   EXT2_XATTR_REFCOUNT_MAX) {
 				ea_idebug(inode, "block %ld refcount %d>%d",
-					  (unsigned long) ce->e_block,
+					  (unsigned long) ce->e_value,
 					  le32_to_cpu(HDR(bh)->h_refcount),
 					  EXT2_XATTR_REFCOUNT_MAX);
 			} else if (!ext2_xattr_cmp(header, HDR(bh))) {
fs/ext4/xattr.c +5 -5
index 886d06e409b6..772948f168c3 100644
@@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		 * This must happen under buffer lock for
 		 * ext4_xattr_block_set() to reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
+		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
 		get_bh(bh);
 		unlock_buffer(bh);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
@@ -1115,8 +1115,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			 * ext4_xattr_block_set() to reliably detect modified
 			 * block
 			 */
-			mb_cache_entry_delete_block(ext4_mb_cache, hash,
-						    bs->bh->b_blocknr);
+			mb_cache_entry_delete(ext4_mb_cache, hash,
+					      bs->bh->b_blocknr);
 			ea_bdebug(bs->bh, "modifying in-place");
 			error = ext4_xattr_set_entry(i, s, handle, inode);
 			if (!error) {
@@ -2238,10 +2238,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			EXT4_ERROR_INODE(inode, "block %lu read error",
-					 (unsigned long) ce->e_block);
+					 (unsigned long) ce->e_value);
 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
 			*pce = ce;
 			return bh;
fs/mbcache.c +21 -22
index b19be429d655..77a5b99d8f92 100644
@@ -10,7 +10,7 @@
 /*
  * Mbcache is a simple key-value store. Keys need not be unique, however
  * key-value pairs are expected to be unique (we use this fact in
- * mb_cache_entry_delete_block()).
+ * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
  * They use hash of a block contents as a key and block number as a value.
@@ -62,15 +62,15 @@ static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
  * @cache - cache where the entry should be created
  * @mask - gfp mask with which the entry should be allocated
  * @key - key of the entry
- * @block - block that contains data
- * @reusable - is the block reusable by other inodes?
+ * @value - value of the entry
+ * @reusable - is the entry reusable by others?
  *
- * Creates entry in @cache with key @key and records that data is stored in
- * block @block. The function returns -EBUSY if entry with the same key
- * and for the same block already exists in cache. Otherwise 0 is returned.
+ * Creates entry in @cache with key @key and value @value. The function returns
+ * -EBUSY if entry with the same key and value already exists in cache.
+ * Otherwise 0 is returned.
  */
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable)
+			  cache_value_t value, bool reusable)
 {
 	struct mb_cache_entry *entry, *dup;
 	struct hlist_bl_node *dup_node;
@@ -91,12 +91,12 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
 	/* One ref for hash, one ref returned */
 	atomic_set(&entry->e_refcnt, 1);
 	entry->e_key = key;
-	entry->e_block = block;
+	entry->e_value = value;
 	entry->e_reusable = reusable;
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) {
-		if (dup->e_key == key && dup->e_block == block) {
+		if (dup->e_key == key && dup->e_value == value) {
 			hlist_bl_unlock(head);
 			kmem_cache_free(mb_entry_cache, entry);
 			return -EBUSY;
@@ -187,13 +187,13 @@ struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
 EXPORT_SYMBOL(mb_cache_entry_find_next);
 
 /*
- * mb_cache_entry_get - get a cache entry by block number (and key)
+ * mb_cache_entry_get - get a cache entry by value (and key)
  * @cache - cache we work with
- * @key - key of block number @block
- * @block - block number
+ * @key - key
+ * @value - value
  */
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block)
+					  cache_value_t value)
 {
 	struct hlist_bl_node *node;
 	struct hlist_bl_head *head;
@@ -202,7 +202,7 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
-		if (entry->e_key == key && entry->e_block == block) {
+		if (entry->e_key == key && entry->e_value == value) {
 			atomic_inc(&entry->e_refcnt);
 			goto out;
 		}
@@ -214,15 +214,14 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
 }
 EXPORT_SYMBOL(mb_cache_entry_get);
 
-/* mb_cache_entry_delete_block - remove information about block from cache
+/* mb_cache_entry_delete - remove a cache entry
  * @cache - cache we work with
- * @key - key of block @block
- * @block - block number
+ * @key - key
+ * @value - value
  *
- * Remove entry from cache @cache with key @key with data stored in @block.
+ * Remove entry from cache @cache with key @key and value @value.
  */
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				 sector_t block)
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key, cache_value_t value)
 {
 	struct hlist_bl_node *node;
 	struct hlist_bl_head *head;
@@ -231,7 +230,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
-		if (entry->e_key == key && entry->e_block == block) {
+		if (entry->e_key == key && entry->e_value == value) {
 			/* We keep hash list reference to keep entry alive */
 			hlist_bl_del_init(&entry->e_hash_list);
 			hlist_bl_unlock(head);
@@ -248,7 +247,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
 	}
 	hlist_bl_unlock(head);
 }
-EXPORT_SYMBOL(mb_cache_entry_delete_block);
+EXPORT_SYMBOL(mb_cache_entry_delete);
 
 /* mb_cache_entry_touch - cache entry got used
  * @cache - cache the entry belongs to
include/linux/mbcache.h +8 -6
index 86c9a8b480c5..e2d9f2f926a4 100644
@@ -9,6 +9,8 @@
 
 struct mb_cache;
 
+typedef sector_t cache_value_t;
+
 struct mb_cache_entry {
 	/* List of entries in cache - protected by cache->c_list_lock */
 	struct list_head	e_list;
@@ -19,15 +21,15 @@ struct mb_cache_entry {
 	u32			e_key;
 	u32			e_referenced:1;
 	u32			e_reusable:1;
-	/* Block number of hashed block - stable during lifetime of the entry */
-	sector_t		e_block;
+	/* User provided value - stable during lifetime of the entry */
+	cache_value_t		e_value;
 };
 
 struct mb_cache *mb_cache_create(int bucket_bits);
 void mb_cache_destroy(struct mb_cache *cache);
 
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable);
+			  cache_value_t value, bool reusable);
 void __mb_cache_entry_free(struct mb_cache_entry *entry);
 static inline int mb_cache_entry_put(struct mb_cache *cache,
 				     struct mb_cache_entry *entry)
@@ -38,10 +40,10 @@ static inline int mb_cache_entry_put(struct mb_cache *cache,
 	return 1;
 }
 
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				  sector_t block);
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key,
+			   cache_value_t value);
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block);
+					  cache_value_t value);
 struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
 						 u32 key);
 struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
Signature · 1 line
2.13.0.219.gdb65acc882-goog
Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
#31 lore raw

Re: [PATCH 23/28] mbcache: make mbcache more generic

Quoted 2 lines · Jan Kara

Can you explain a bit more what do you mean by "make it more generic" as it seems you just rename a couple of things here...

The change is really just that, having names that are more generic which do not limit use cases to block sharing. In a subsequent patch in the series ("[PATCH v4 27/28] ext4: xattr inode deduplication"), we start using the mbcache code to share xattr inodes. With that patch, old mb_cache_entry.e_block field could be holding either a block number or an inode number, so I renamed things to make them more generic.

reviewer
#32 lore raw

Re: [PATCH 23/28] mbcache: make mbcache more generic

Quoted 11 lines · Tahsin Erdogan
Quoted 2 lines · Jan Kara

Can you explain a bit more what do you mean by "make it more generic" as it seems you just rename a couple of things here...

The change is really just that, having names that are more generic which do not limit use cases to block sharing. In a subsequent patch in the series ("[PATCH v4 27/28] ext4: xattr inode deduplication"), we start using the mbcache code to share xattr inodes. With that patch, old mb_cache_entry.e_block field could be holding either a block number or an inode number, so I renamed things to make them more generic.

OK, then I'd suggest to change title to "mbcache: make mbcache naming more generic" and explain what you wrote here in the changelog. Thanks!

Honza

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
#33 lore raw

PATCH v2 23/31 mbcache: make mbcache naming more generic

Make names more generic so that mbcache usage is not limited to block sharing. In a subsequent patch in the series
("ext4: xattr inode deduplication"), we start using the mbcache code for sharing xattr inodes. With that patch, old mb_cache_entry.e_block field could be holding either a block number or an inode number.

---
v2: updated commit title and description

 fs/ext2/xattr.c         | 18 +++++++++---------
 fs/ext4/xattr.c         | 10 +++++-----
 fs/mbcache.c            | 43 +++++++++++++++++++++----------------------
 include/linux/mbcache.h | 11 +++++------
 4 files changed, 40 insertions(+), 42 deletions(-)
fs/ext2/xattr.c +9 -9
index fbdb8f171893..1e5f76070580 100644
@@ -493,8 +493,8 @@ bad_block:		ext2_error(sb, "ext2_xattr_set",
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect modified block
 			 */
-			mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache,
-						    hash, bh->b_blocknr);
+			mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash,
+					      bh->b_blocknr);
 
 			/* keep the buffer locked while modifying it. */
 		} else {
@@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect freed block
 			 */
-			mb_cache_entry_delete_block(ext2_mb_cache,
-						    hash, old_bh->b_blocknr);
+			mb_cache_entry_delete(ext2_mb_cache, hash,
+					      old_bh->b_blocknr);
 			/* Free the old block. */
 			ea_bdebug(old_bh, "freeing");
 			ext2_free_blocks(inode, old_bh->b_blocknr, 1);
@@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode)
 		 * This must happen under buffer lock for ext2_xattr_set2() to
 		 * reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache,
-					    hash, bh->b_blocknr);
+		mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash,
+				      bh->b_blocknr);
 		ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
 		get_bh(bh);
 		bforget(bh);
@@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			ext2_error(inode->i_sb, "ext2_xattr_cache_find",
 				"inode %ld: block %ld read error",
-				inode->i_ino, (unsigned long) ce->e_block);
+				inode->i_ino, (unsigned long) ce->e_value);
 		} else {
 			lock_buffer(bh);
 			/*
@@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 			} else if (le32_to_cpu(HDR(bh)->h_refcount) >
 				   EXT2_XATTR_REFCOUNT_MAX) {
 				ea_idebug(inode, "block %ld refcount %d>%d",
-					  (unsigned long) ce->e_block,
+					  (unsigned long) ce->e_value,
 					  le32_to_cpu(HDR(bh)->h_refcount),
 					  EXT2_XATTR_REFCOUNT_MAX);
 			} else if (!ext2_xattr_cmp(header, HDR(bh))) {
fs/ext4/xattr.c +5 -5
index c09fcffb0878..0b43e0e52e26 100644
@@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		 * This must happen under buffer lock for
 		 * ext4_xattr_block_set() to reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
+		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
 		get_bh(bh);
 		unlock_buffer(bh);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
@@ -1115,8 +1115,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			 * ext4_xattr_block_set() to reliably detect modified
 			 * block
 			 */
-			mb_cache_entry_delete_block(ext4_mb_cache, hash,
-						    bs->bh->b_blocknr);
+			mb_cache_entry_delete(ext4_mb_cache, hash,
+					      bs->bh->b_blocknr);
 			ea_bdebug(bs->bh, "modifying in-place");
 			error = ext4_xattr_set_entry(i, s, handle, inode);
 			if (!error) {
@@ -2238,10 +2238,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			EXT4_ERROR_INODE(inode, "block %lu read error",
-					 (unsigned long) ce->e_block);
+					 (unsigned long) ce->e_value);
 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
 			*pce = ce;
 			return bh;
fs/mbcache.c +21 -22

104 lines not on this page · raw message

include/linux/mbcache.h +5 -6
index 86c9a8b480c5..e1bc73414983 100644
@@ -19,15 +19,15 @@ struct mb_cache_entry {
 	u32			e_key;
 	u32			e_referenced:1;
 	u32			e_reusable:1;
-	/* Block number of hashed block - stable during lifetime of the entry */
-	sector_t		e_block;
+	/* User provided value - stable during lifetime of the entry */
+	u64			e_value;
 };
 
 struct mb_cache *mb_cache_create(int bucket_bits);
 void mb_cache_destroy(struct mb_cache *cache);
 
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable);
+			  u64 value, bool reusable);
 void __mb_cache_entry_free(struct mb_cache_entry *entry);
 static inline int mb_cache_entry_put(struct mb_cache *cache,
 				     struct mb_cache_entry *entry)
@@ -38,10 +38,9 @@ static inline int mb_cache_entry_put(struct mb_cache *cache,
 	return 1;
 }
 
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				  sector_t block);
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value);
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block);
+					  u64 value);
 struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
 						 u32 key);
 struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
Signature · 1 line
2.13.1.518.g3df882009-goog
Reviewed-by on v2 23/31
#34 lore raw

Re: [PATCH v2 23/31] mbcache: make mbcache naming more generic

Quoted 8 lines · Tahsin Erdogan

Make names more generic so that mbcache usage is not limited to block sharing. In a subsequent patch in the series
("ext4: xattr inode deduplication"), we start using the mbcache code for sharing xattr inodes. With that patch, old mb_cache_entry.e_block field could be holding either a block number or an inode number.

Quoted 259 lines

---
v2: updated commit title and description

fs/ext2/xattr.c         | 18 +++++++++---------
fs/ext4/xattr.c         | 10 +++++-----
fs/mbcache.c            | 43 +++++++++++++++++++++----------------------
include/linux/mbcache.h | 11 +++++------
4 files changed, 40 insertions(+), 42 deletions(-)
fs/ext2/xattr.c +9 -9
index fbdb8f171893..1e5f76070580 100644
@@ -493,8 +493,8 @@ bad_block:		ext2_error(sb, "ext2_xattr_set",
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect modified block
 			 */
-			mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache,
-						    hash, bh->b_blocknr);
+			mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash,
+					      bh->b_blocknr);
 
 			/* keep the buffer locked while modifying it. */
 		} else {
@@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect freed block
 			 */
-			mb_cache_entry_delete_block(ext2_mb_cache,
-						    hash, old_bh->b_blocknr);
+			mb_cache_entry_delete(ext2_mb_cache, hash,
+					      old_bh->b_blocknr);
 			/* Free the old block. */
 			ea_bdebug(old_bh, "freeing");
 			ext2_free_blocks(inode, old_bh->b_blocknr, 1);
@@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode)
 		 * This must happen under buffer lock for ext2_xattr_set2() to
 		 * reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache,
-					    hash, bh->b_blocknr);
+		mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash,
+				      bh->b_blocknr);
 		ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
 		get_bh(bh);
 		bforget(bh);
@@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			ext2_error(inode->i_sb, "ext2_xattr_cache_find",
 				"inode %ld: block %ld read error",
-				inode->i_ino, (unsigned long) ce->e_block);
+				inode->i_ino, (unsigned long) ce->e_value);
 		} else {
 			lock_buffer(bh);
 			/*
@@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 			} else if (le32_to_cpu(HDR(bh)->h_refcount) >
 				   EXT2_XATTR_REFCOUNT_MAX) {
 				ea_idebug(inode, "block %ld refcount %d>%d",
-					  (unsigned long) ce->e_block,
+					  (unsigned long) ce->e_value,
 					  le32_to_cpu(HDR(bh)->h_refcount),
 					  EXT2_XATTR_REFCOUNT_MAX);
 			} else if (!ext2_xattr_cmp(header, HDR(bh))) {
fs/ext4/xattr.c +5 -5
index c09fcffb0878..0b43e0e52e26 100644
@@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		 * This must happen under buffer lock for
 		 * ext4_xattr_block_set() to reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
+		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
 		get_bh(bh);
 		unlock_buffer(bh);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
@@ -1115,8 +1115,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			 * ext4_xattr_block_set() to reliably detect modified
 			 * block
 			 */
-			mb_cache_entry_delete_block(ext4_mb_cache, hash,
-						    bs->bh->b_blocknr);
+			mb_cache_entry_delete(ext4_mb_cache, hash,
+					      bs->bh->b_blocknr);
 			ea_bdebug(bs->bh, "modifying in-place");
 			error = ext4_xattr_set_entry(i, s, handle, inode);
 			if (!error) {
@@ -2238,10 +2238,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			EXT4_ERROR_INODE(inode, "block %lu read error",
-					 (unsigned long) ce->e_block);
+					 (unsigned long) ce->e_value);
 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
 			*pce = ce;
 			return bh;
fs/mbcache.c +21 -22
index b19be429d655..45a8d52dc991 100644
@@ -10,7 +10,7 @@
 /*
 * Mbcache is a simple key-value store. Keys need not be unique, however
 * key-value pairs are expected to be unique (we use this fact in
- * mb_cache_entry_delete_block()).
+ * mb_cache_entry_delete()).
 *
 * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
 * They use hash of a block contents as a key and block number as a value.
@@ -62,15 +62,15 @@ static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
 * @cache - cache where the entry should be created
 * @mask - gfp mask with which the entry should be allocated
 * @key - key of the entry
- * @block - block that contains data
- * @reusable - is the block reusable by other inodes?
+ * @value - value of the entry
+ * @reusable - is the entry reusable by others?
 *
- * Creates entry in @cache with key @key and records that data is stored in
- * block @block. The function returns -EBUSY if entry with the same key
- * and for the same block already exists in cache. Otherwise 0 is returned.
+ * Creates entry in @cache with key @key and value @value. The function returns
+ * -EBUSY if entry with the same key and value already exists in cache.
+ * Otherwise 0 is returned.
 */
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable)
+			  u64 value, bool reusable)
 {
 	struct mb_cache_entry *entry, *dup;
 	struct hlist_bl_node *dup_node;
@@ -91,12 +91,12 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
 	/* One ref for hash, one ref returned */
 	atomic_set(&entry->e_refcnt, 1);
 	entry->e_key = key;
-	entry->e_block = block;
+	entry->e_value = value;
 	entry->e_reusable = reusable;
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) {
-		if (dup->e_key == key && dup->e_block == block) {
+		if (dup->e_key == key && dup->e_value == value) {
 			hlist_bl_unlock(head);
 			kmem_cache_free(mb_entry_cache, entry);
 			return -EBUSY;
@@ -187,13 +187,13 @@ struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
 EXPORT_SYMBOL(mb_cache_entry_find_next);
 
 /*
- * mb_cache_entry_get - get a cache entry by block number (and key)
+ * mb_cache_entry_get - get a cache entry by value (and key)
 * @cache - cache we work with
- * @key - key of block number @block
- * @block - block number
+ * @key - key
+ * @value - value
 */
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block)
+					  u64 value)
 {
 	struct hlist_bl_node *node;
 	struct hlist_bl_head *head;
@@ -202,7 +202,7 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
-		if (entry->e_key == key && entry->e_block == block) {
+		if (entry->e_key == key && entry->e_value == value) {
 			atomic_inc(&entry->e_refcnt);
 			goto out;
 		}
@@ -214,15 +214,14 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
 }
 EXPORT_SYMBOL(mb_cache_entry_get);
 
-/* mb_cache_entry_delete_block - remove information about block from cache
+/* mb_cache_entry_delete - remove a cache entry
 * @cache - cache we work with
- * @key - key of block @block
- * @block - block number
+ * @key - key
+ * @value - value
 *
- * Remove entry from cache @cache with key @key with data stored in @block.
+ * Remove entry from cache @cache with key @key and value @value.
 */
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				 sector_t block)
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value)
 {
 	struct hlist_bl_node *node;
 	struct hlist_bl_head *head;
@@ -231,7 +230,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
-		if (entry->e_key == key && entry->e_block == block) {
+		if (entry->e_key == key && entry->e_value == value) {
 			/* We keep hash list reference to keep entry alive */
 			hlist_bl_del_init(&entry->e_hash_list);
 			hlist_bl_unlock(head);
@@ -248,7 +247,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
 	}
 	hlist_bl_unlock(head);
 }
-EXPORT_SYMBOL(mb_cache_entry_delete_block);
+EXPORT_SYMBOL(mb_cache_entry_delete);
 
 /* mb_cache_entry_touch - cache entry got used
 * @cache - cache the entry belongs to
include/linux/mbcache.h +5 -7
index 86c9a8b480c5..e1bc73414983 100644
@@ -19,15 +19,15 @@ struct mb_cache_entry {
 	u32			e_key;
 	u32			e_referenced:1;
 	u32			e_reusable:1;
-	/* Block number of hashed block - stable during lifetime of the entry */
-	sector_t		e_block;
+	/* User provided value - stable during lifetime of the entry */
+	u64			e_value;
 };
 
 struct mb_cache *mb_cache_create(int bucket_bits);
 void mb_cache_destroy(struct mb_cache *cache);
 
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable);
+			  u64 value, bool reusable);
 void __mb_cache_entry_free(struct mb_cache_entry *entry);
 static inline int mb_cache_entry_put(struct mb_cache *cache,
 				     struct mb_cache_entry *entry)
@@ -38,10 +38,9 @@ static inline int mb_cache_entry_put(struct mb_cache *cache,
 	return 1;
 }
 
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				  sector_t block);
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value);
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block);
+					  u64 value);
 struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
 						 u32 key);
 struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
--
Quoted 2 lines

2.13.1.518.g3df882009-goog

Cheers, Andreas

#35 lore raw

Re: [PATCH v2 23/31] mbcache: make mbcache naming more generic

In reply to Tahsin Erdogan
Quoted 6 lines · Tahsin Erdogan

Make names more generic so that mbcache usage is not limited to block sharing. In a subsequent patch in the series
("ext4: xattr inode deduplication"), we start using the mbcache code for sharing xattr inodes. With that patch, old mb_cache_entry.e_block field could be holding either a block number or an inode number.

Actually, looking at the later 28/31 patch made me come back to add a few comments to this patch. Not strictly required, but I think it makes the code a bit more clear.

Quoted 15 lines

---
v2: updated commit title and description

fs/ext2/xattr.c         | 18 +++++++++---------
fs/ext4/xattr.c         | 10 +++++-----
fs/mbcache.c            | 43 +++++++++++++++++++++----------------------
include/linux/mbcache.h | 11 +++++------
4 files changed, 40 insertions(+), 42 deletions(-)
fs/ext2/xattr.c +0 -0
index fbdb8f171893..1e5f76070580 100644

fs/ext2/xattr.c bad_block: ext2_error(sb, "ext2_xattr_set", · line 497

Quoted 7 lines
fs/ext2/xattr.c +2 -2
@@ -493,8 +493,8 @@ bad_block:		ext2_error(sb, "ext2_xattr_set",
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect modified block
 			 */
-			mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache,
-						    hash, bh->b_blocknr);
+			mb_cache_entry_delete(EXT2_SB(sb)->s_mb_cache, hash,
+					      bh->b_blocknr);

Since we now also have the ea_inode cache, it would be better to rename s_mb_cache to s_mb_block_cache to make it more clear what it is. That isn't strictly needed for ext2, but better to keep it consistent with ext4.

fs/ext2/xattr.c ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, · line 725

Quoted 10 lines
fs/ext2/xattr.c +2 -2
 			/* keep the buffer locked while modifying it. */
 		} else {
@@ -721,8 +721,8 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
 			 * This must happen under buffer lock for
 			 * ext2_xattr_set2() to reliably detect freed block
 			 */
-			mb_cache_entry_delete_block(ext2_mb_cache,
-						    hash, old_bh->b_blocknr);
+			mb_cache_entry_delete(ext2_mb_cache, hash,
+					      old_bh->b_blocknr);

Minor nit - having a function-local variable named "ext2_mb_cache" and "ext4_mb_cache" makes it look like this is a global variable. I think this name is left over from when it _was_ actually a single global cache rather than a per-filesystem cache. It would be better to use a name like "mb_block_cache" to make it clear that this is the local block cache.

Quoted 42 lines
fs/ext2/xattr.c +5 -5
 			/* Free the old block. */
 			ea_bdebug(old_bh, "freeing");
 			ext2_free_blocks(inode, old_bh->b_blocknr, 1);
@@ -795,8 +795,8 @@ ext2_xattr_delete_inode(struct inode *inode)
 		 * This must happen under buffer lock for ext2_xattr_set2() to
 		 * reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache,
-					    hash, bh->b_blocknr);
+		mb_cache_entry_delete(EXT2_SB(inode->i_sb)->s_mb_cache, hash,
+				      bh->b_blocknr);
 		ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
 		get_bh(bh);
 		bforget(bh);
@@ -907,11 +907,11 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			ext2_error(inode->i_sb, "ext2_xattr_cache_find",
 				"inode %ld: block %ld read error",
-				inode->i_ino, (unsigned long) ce->e_block);
+				inode->i_ino, (unsigned long) ce->e_value);
 		} else {
 			lock_buffer(bh);
 			/*
@@ -931,7 +931,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
 			} else if (le32_to_cpu(HDR(bh)->h_refcount) >
 				   EXT2_XATTR_REFCOUNT_MAX) {
 				ea_idebug(inode, "block %ld refcount %d>%d",
-					  (unsigned long) ce->e_block,
+					  (unsigned long) ce->e_value,
 					  le32_to_cpu(HDR(bh)->h_refcount),
 					  EXT2_XATTR_REFCOUNT_MAX);
 			} else if (!ext2_xattr_cmp(header, HDR(bh))) {
fs/ext4/xattr.c +0 -0
index c09fcffb0878..0b43e0e52e26 100644

fs/ext4/xattr.c ext4_xattr_release_block(handle_t *handle, struct inode *inode, · line 681

Quoted 5 lines
fs/ext4/xattr.c +1 -1
@@ -678,7 +678,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		 * This must happen under buffer lock for
 		 * ext4_xattr_block_set() to reliably detect freed block
 		 */
-		mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
+		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);

This local variable should be named "mb_block_cache" or similar.

fs/ext4/xattr.c ext4_xattr_block_set(handle_t *handle, struct inode *inode, · line 1119

Quoted 11 lines
fs/ext4/xattr.c +2 -2
 		get_bh(bh);
 		unlock_buffer(bh);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
@@ -1115,8 +1115,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			 * ext4_xattr_block_set() to reliably detect modified
 			 * block
 			 */
-			mb_cache_entry_delete_block(ext4_mb_cache, hash,
-						    bs->bh->b_blocknr);
+			mb_cache_entry_delete(ext4_mb_cache, hash,
+					      bs->bh->b_blocknr);

s/ext4_mb_cache/mb_block_cache/

fs/ext4/xattr.c ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, · line 2244

Quoted 13 lines
fs/ext4/xattr.c +2 -2
 			ea_bdebug(bs->bh, "modifying in-place");
 			error = ext4_xattr_set_entry(i, s, handle, inode);
 			if (!error) {
@@ -2238,10 +2238,10 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
 	while (ce) {
 		struct buffer_head *bh;
 
-		bh = sb_bread(inode->i_sb, ce->e_block);
+		bh = sb_bread(inode->i_sb, ce->e_value);
 		if (!bh) {
 			EXT4_ERROR_INODE(inode, "block %lu read error",
-					 (unsigned long) ce->e_block);
+					 (unsigned long) ce->e_value);

(style) no space after typecast

Quoted 156 lines
fs/ext4/xattr.c +0 -0
 		} else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
 			*pce = ce;
 			return bh;
fs/mbcache.c +21 -22
index b19be429d655..45a8d52dc991 100644
@@ -10,7 +10,7 @@
 /*
 * Mbcache is a simple key-value store. Keys need not be unique, however
 * key-value pairs are expected to be unique (we use this fact in
- * mb_cache_entry_delete_block()).
+ * mb_cache_entry_delete()).
 *
 * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
 * They use hash of a block contents as a key and block number as a value.
@@ -62,15 +62,15 @@ static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
 * @cache - cache where the entry should be created
 * @mask - gfp mask with which the entry should be allocated
 * @key - key of the entry
- * @block - block that contains data
- * @reusable - is the block reusable by other inodes?
+ * @value - value of the entry
+ * @reusable - is the entry reusable by others?
 *
- * Creates entry in @cache with key @key and records that data is stored in
- * block @block. The function returns -EBUSY if entry with the same key
- * and for the same block already exists in cache. Otherwise 0 is returned.
+ * Creates entry in @cache with key @key and value @value. The function returns
+ * -EBUSY if entry with the same key and value already exists in cache.
+ * Otherwise 0 is returned.
 */
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable)
+			  u64 value, bool reusable)
 {
 	struct mb_cache_entry *entry, *dup;
 	struct hlist_bl_node *dup_node;
@@ -91,12 +91,12 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
 	/* One ref for hash, one ref returned */
 	atomic_set(&entry->e_refcnt, 1);
 	entry->e_key = key;
-	entry->e_block = block;
+	entry->e_value = value;
 	entry->e_reusable = reusable;
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) {
-		if (dup->e_key == key && dup->e_block == block) {
+		if (dup->e_key == key && dup->e_value == value) {
 			hlist_bl_unlock(head);
 			kmem_cache_free(mb_entry_cache, entry);
 			return -EBUSY;
@@ -187,13 +187,13 @@ struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
 EXPORT_SYMBOL(mb_cache_entry_find_next);
 
 /*
- * mb_cache_entry_get - get a cache entry by block number (and key)
+ * mb_cache_entry_get - get a cache entry by value (and key)
 * @cache - cache we work with
- * @key - key of block number @block
- * @block - block number
+ * @key - key
+ * @value - value
 */
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block)
+					  u64 value)
 {
 	struct hlist_bl_node *node;
 	struct hlist_bl_head *head;
@@ -202,7 +202,7 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
-		if (entry->e_key == key && entry->e_block == block) {
+		if (entry->e_key == key && entry->e_value == value) {
 			atomic_inc(&entry->e_refcnt);
 			goto out;
 		}
@@ -214,15 +214,14 @@ struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
 }
 EXPORT_SYMBOL(mb_cache_entry_get);
 
-/* mb_cache_entry_delete_block - remove information about block from cache
+/* mb_cache_entry_delete - remove a cache entry
 * @cache - cache we work with
- * @key - key of block @block
- * @block - block number
+ * @key - key
+ * @value - value
 *
- * Remove entry from cache @cache with key @key with data stored in @block.
+ * Remove entry from cache @cache with key @key and value @value.
 */
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				 sector_t block)
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value)
 {
 	struct hlist_bl_node *node;
 	struct hlist_bl_head *head;
@@ -231,7 +230,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
 	head = mb_cache_entry_head(cache, key);
 	hlist_bl_lock(head);
 	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {
-		if (entry->e_key == key && entry->e_block == block) {
+		if (entry->e_key == key && entry->e_value == value) {
 			/* We keep hash list reference to keep entry alive */
 			hlist_bl_del_init(&entry->e_hash_list);
 			hlist_bl_unlock(head);
@@ -248,7 +247,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
 	}
 	hlist_bl_unlock(head);
 }
-EXPORT_SYMBOL(mb_cache_entry_delete_block);
+EXPORT_SYMBOL(mb_cache_entry_delete);
 
 /* mb_cache_entry_touch - cache entry got used
 * @cache - cache the entry belongs to
include/linux/mbcache.h +5 -7
index 86c9a8b480c5..e1bc73414983 100644
@@ -19,15 +19,15 @@ struct mb_cache_entry {
 	u32			e_key;
 	u32			e_referenced:1;
 	u32			e_reusable:1;
-	/* Block number of hashed block - stable during lifetime of the entry */
-	sector_t		e_block;
+	/* User provided value - stable during lifetime of the entry */
+	u64			e_value;
 };
 
 struct mb_cache *mb_cache_create(int bucket_bits);
 void mb_cache_destroy(struct mb_cache *cache);
 
 int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
-			  sector_t block, bool reusable);
+			  u64 value, bool reusable);
 void __mb_cache_entry_free(struct mb_cache_entry *entry);
 static inline int mb_cache_entry_put(struct mb_cache *cache,
 				     struct mb_cache_entry *entry)
@@ -38,10 +38,9 @@ static inline int mb_cache_entry_put(struct mb_cache *cache,
 	return 1;
 }
 
-void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key,
-				  sector_t block);
+void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value);
 struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
-					  sector_t block);
+					  u64 value);
 struct mb_cache_entry *mb_cache_entry_find_first(struct mb_cache *cache,
 						 u32 key);
 struct mb_cache_entry *mb_cache_entry_find_next(struct mb_cache *cache,
--
Quoted 2 lines

2.13.1.518.g3df882009-goog

Cheers, Andreas

#36 lore raw

Re: [PATCH v2 23/31] mbcache: make mbcache naming more generic

Hi Andreas, I have incorporated your suggestions into another patch that renames things in ext2/ext4 ("[PATCH 24/32] ext2, ext4: make mb block cache names more explicit").

Quoted 3 lines

Since we now also have the ea_inode cache, it would be better to rename s_mb_cache to s_mb_block_cache to make it more clear what it is. That isn't strictly needed for ext2, but better to keep it consistent with ext4.

Done

Quoted 5 lines

Minor nit - having a function-local variable named "ext2_mb_cache" and "ext4_mb_cache" makes it look like this is a global variable. I think this name is left over from when it _was_ actually a single global cache rather than a per-filesystem cache. It would be better to use a name like "mb_block_cache" to make it clear that this is the local block cache.

Done

Quoted 1 line

This local variable should be named "mb_block_cache" or similar.

Done

Quoted 1 line

s/ext4_mb_cache/mb_block_cache/

Done

Quoted 1 line

(style) no space after typecast

Fixed

#37 lore raw

PATCH 24/28 ext4: rename mb block cache functions

In reply to Tahsin Erdogan

There will be a second cache instance that tracks ea_inodes. Make existing names more explicit so that it is clear that they refer to xattr block cache.

---
 fs/ext4/xattr.c | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)
fs/ext4/xattr.c +20 -16
index 772948f168c3..3ee7e2f68476 100644
@@ -72,10 +72,11 @@
 # define ea_bdebug(bh, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
 #endif
 
-static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
-static struct buffer_head *ext4_xattr_cache_find(struct inode *,
-						 struct ext4_xattr_header *,
-						 struct mb_cache_entry **);
+static void ext4_xattr_block_cache_insert(struct mb_cache *,
+					  struct buffer_head *);
+static struct buffer_head *
+ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
+			    struct mb_cache_entry **);
 static void ext4_xattr_rehash(struct ext4_xattr_header *,
 			      struct ext4_xattr_entry *);
 
@@ -395,7 +396,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
 		error = -EFSCORRUPTED;
 		goto cleanup;
 	}
-	ext4_xattr_cache_insert(ext4_mb_cache, bh);
+	ext4_xattr_block_cache_insert(ext4_mb_cache, bh);
 	entry = BFIRST(bh);
 	error = ext4_xattr_find_entry(&entry, name_index, name, 1);
 	if (error)
@@ -563,7 +564,7 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
 		error = -EFSCORRUPTED;
 		goto cleanup;
 	}
-	ext4_xattr_cache_insert(ext4_mb_cache, bh);
+	ext4_xattr_block_cache_insert(ext4_mb_cache, bh);
 	error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
 
 cleanup:
@@ -1123,8 +1124,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 				if (!IS_LAST_ENTRY(s->first))
 					ext4_xattr_rehash(header(s->base),
 							  s->here);
-				ext4_xattr_cache_insert(ext4_mb_cache,
-					bs->bh);
+				ext4_xattr_block_cache_insert(ext4_mb_cache,
+							      bs->bh);
 			}
 			ext4_xattr_block_csum_set(inode, bs->bh);
 			unlock_buffer(bs->bh);
@@ -1177,7 +1178,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 
 inserted:
 	if (!IS_LAST_ENTRY(s->first)) {
-		new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
+		new_bh = ext4_xattr_block_cache_find(inode, header(s->base),
+						     &ce);
 		if (new_bh) {
 			/* We found an identical block in the cache. */
 			if (new_bh == bs->bh)
@@ -1292,7 +1294,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			ext4_xattr_block_csum_set(inode, new_bh);
 			set_buffer_uptodate(new_bh);
 			unlock_buffer(new_bh);
-			ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
+			ext4_xattr_block_cache_insert(ext4_mb_cache, new_bh);
 			error = ext4_handle_dirty_metadata(handle, inode,
 							   new_bh);
 			if (error)
@@ -2150,15 +2152,16 @@ void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
 }
 
 /*
- * ext4_xattr_cache_insert()
+ * ext4_xattr_block_cache_insert()
  *
- * Create a new entry in the extended attribute cache, and insert
+ * Create a new entry in the extended attribute block cache, and insert
  * it unless such an entry is already in the cache.
  *
  * Returns 0, or a negative error number on failure.
  */
 static void
-ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
+ext4_xattr_block_cache_insert(struct mb_cache *ext4_mb_cache,
+			      struct buffer_head *bh)
 {
 	struct ext4_xattr_header *header = BHDR(bh);
 	__u32 hash = le32_to_cpu(header->h_hash);
@@ -2216,7 +2219,7 @@ ext4_xattr_cmp(struct ext4_xattr_header *header1,
 }
 
 /*
- * ext4_xattr_cache_find()
+ * ext4_xattr_block_cache_find()
  *
  * Find an identical extended attribute block.
  *
@@ -2224,8 +2227,9 @@ ext4_xattr_cmp(struct ext4_xattr_header *header1,
  * not found or an error occurred.
  */
 static struct buffer_head *
-ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
-		      struct mb_cache_entry **pce)
+ext4_xattr_block_cache_find(struct inode *inode,
+			    struct ext4_xattr_header *header,
+			    struct mb_cache_entry **pce)
 {
 	__u32 hash = le32_to_cpu(header->h_hash);
 	struct mb_cache_entry *ce;
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#38 lore raw

PATCH 25/28 ext4: add ext4_is_quota_file()

In reply to Tahsin Erdogan

IS_NOQUOTA() indicates whether quota is disabled for an inode. Ext4 also uses it to check whether an inode is for a quota file. The distinction currently doesn't matter because quota is disabled only for the quota files. When we start disabling quota for other inodes in the future, we will want to make the distinction clear.

Replace IS_NOQUOTA() call with ext4_is_quota_file() at places where we are checking for quota files.

---
 fs/ext4/ext4.h        | 2 ++
 fs/ext4/inode.c       | 2 +-
 fs/ext4/ioctl.c       | 4 ++--
 fs/ext4/mballoc.c     | 2 +-
 fs/ext4/move_extent.c | 2 +-
 5 files changed, 7 insertions(+), 5 deletions(-)
fs/ext4/ext4.h +2 -0
index 580fdb753f29..d79d8d7bee88 100644
@@ -2099,6 +2099,8 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
+#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+
 /*
  * This structure is stuffed into the struct file's private_data field
  * for directories.  It is where we put information so that we can do
fs/ext4/inode.c +1 -1
index 8ee20b586567..cf91532765a4 100644
@@ -739,7 +739,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 		if (map->m_flags & EXT4_MAP_NEW &&
 		    !(map->m_flags & EXT4_MAP_UNWRITTEN) &&
 		    !(flags & EXT4_GET_BLOCKS_ZERO) &&
-		    !IS_NOQUOTA(inode) &&
+		    !ext4_is_quota_file(inode) &&
 		    ext4_should_order_data(inode)) {
 			if (flags & EXT4_GET_BLOCKS_IO_SUBMIT)
 				ret = ext4_jbd2_inode_add_wait(handle, inode);
fs/ext4/ioctl.c +2 -2
index 0c21e22acd74..dde8deb11e59 100644
@@ -218,7 +218,7 @@ static int ext4_ioctl_setflags(struct inode *inode,
 	unsigned int jflag;
 
 	/* Is it quota file? Do not allow user to mess with it */
-	if (IS_NOQUOTA(inode))
+	if (ext4_is_quota_file(inode))
 		goto flags_out;
 
 	oldflags = ei->i_flags;
@@ -342,7 +342,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	err = -EPERM;
 	inode_lock(inode);
 	/* Is it quota file? Do not allow user to mess with it */
-	if (IS_NOQUOTA(inode))
+	if (ext4_is_quota_file(inode))
 		goto out_unlock;
 
 	err = ext4_get_inode_loc(inode, &iloc);
fs/ext4/mballoc.c +1 -1
index b7928cddd539..d109a2a2fea0 100644
@@ -4464,7 +4464,7 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 	trace_ext4_request_blocks(ar);
 
 	/* Allow to use superuser reservation for quota file */
-	if (IS_NOQUOTA(ar->inode))
+	if (ext4_is_quota_file(ar->inode))
 		ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
 
 	if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
fs/ext4/move_extent.c +1 -1
index c992ef2c2f94..9bb36909ec92 100644
@@ -484,7 +484,7 @@ mext_check_arguments(struct inode *orig_inode,
 		return -EBUSY;
 	}
 
-	if (IS_NOQUOTA(orig_inode) || IS_NOQUOTA(donor_inode)) {
+	if (ext4_is_quota_file(orig_inode) && ext4_is_quota_file(donor_inode)) {
 		ext4_debug("ext4 move extent: The argument files should "
 			"not be quota files [ino:orig %lu, donor %lu]\n",
 			orig_inode->i_ino, donor_inode->i_ino);
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#39 lore raw

PATCH 26/28 ext4: cleanup transaction restarts during inode deletion

In reply to Tahsin Erdogan

During inode deletion, journal credits that will be needed are hard to determine, that is why we have journal extend/restart calls in several places. Whenever a transaction is restarted, filesystem must be in a consistent state because there is no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of journal extend/restart logic. It also handles getting jbd2 write access and dirty metadata calls. This function is called at every iteration of handling an ea_inode reference.

---
 fs/ext4/inode.c |  66 ++++-----------
 fs/ext4/xattr.c | 257 ++++++++++++++++++++++++++++++++++++--------------------
 fs/ext4/xattr.h |   3 +-
 3 files changed, 183 insertions(+), 143 deletions(-)
fs/ext4/inode.c +17 -49
index cf91532765a4..4d6936f0d8a4 100644
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode)
 	 */
 	sb_start_intwrite(inode->i_sb);
 
-	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
+	if (!IS_NOQUOTA(inode))
+		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+				 ext4_blocks_for_truncate(inode)+extra_credits);
 	if (IS_ERR(handle)) {
 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode)
 		sb_end_intwrite(inode->i_sb);
 		goto no_delete;
 	}
+
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);
-
-	/*
-	 * Delete xattr inode before deleting the main inode.
-	 */
-	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
-	if (err) {
-		ext4_warning(inode->i_sb,
-			     "couldn't delete inode's xattr (err %d)", err);
-		goto stop_handle;
-	}
-
-	if (!IS_NOQUOTA(inode))
-		extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-	if (!ext4_handle_has_enough_credits(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits)) {
-		err = ext4_journal_extend(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-			goto stop_handle;
-		}
-	}
-
 	inode->i_size = 0;
 	err = ext4_mark_inode_dirty(handle, inode);
 	if (err) {
@@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode)
 		}
 	}
 
-	/*
-	 * ext4_ext_truncate() doesn't reserve any slop when it
-	 * restarts journal transactions; therefore there may not be
-	 * enough credits left in the handle to remove the inode from
-	 * the orphan list and set the dtime field.
-	 */
-	if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
-		err = ext4_journal_extend(handle, extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle, extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-		stop_handle:
-			ext4_journal_stop(handle);
-			ext4_orphan_del(NULL, inode);
-			sb_end_intwrite(inode->i_sb);
-			goto no_delete;
-		}
+	/* Remove xattr references. */
+	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+				      extra_credits);
+	if (err) {
+		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+	stop_handle:
+		ext4_journal_stop(handle);
+		ext4_orphan_del(NULL, inode);
+		sb_end_intwrite(inode->i_sb);
+		ext4_xattr_inode_array_free(ea_inode_array);
+		goto no_delete;
 	}
 
 	/*
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode)
 		ext4_clear_inode(inode);
 	else
 		ext4_free_inode(handle, inode);
-
 	ext4_journal_stop(handle);
 	sb_end_intwrite(inode->i_sb);
 	ext4_xattr_inode_array_free(ea_inode_array);
fs/ext4/xattr.c +164 -93

311 lines not on this page · raw message

fs/ext4/xattr.h +2 -1
index adf761518a73..b2005a2716d9 100644
@@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-				   struct ext4_xattr_inode_array **array);
+				   struct ext4_xattr_inode_array **array,
+				   int extra_credits);
 extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#40 lore raw

PATCH v2 26/28 ext4: cleanup transaction restarts during inode deletion

During inode deletion, journal credits that will be needed are hard to determine, that is why we have journal extend/restart calls in several places. Whenever a transaction is restarted, filesystem must be in a consistent state because there is no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of journal extend/restart logic. It also handles getting jbd2 write access and dirty metadata calls. This function is called at every iteration of handling an ea_inode reference.

---
v2: made ext4_xattr_ensure_credits() static

 fs/ext4/inode.c |  66 ++++-----------
 fs/ext4/xattr.c | 257 ++++++++++++++++++++++++++++++++++++--------------------
 fs/ext4/xattr.h |   3 +-
 3 files changed, 183 insertions(+), 143 deletions(-)
fs/ext4/inode.c +17 -49
index cf91532765a4..4d6936f0d8a4 100644
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode)
 	 */
 	sb_start_intwrite(inode->i_sb);
 
-	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
+	if (!IS_NOQUOTA(inode))
+		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+				 ext4_blocks_for_truncate(inode)+extra_credits);
 	if (IS_ERR(handle)) {
 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode)
 		sb_end_intwrite(inode->i_sb);
 		goto no_delete;
 	}
+
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);
-
-	/*
-	 * Delete xattr inode before deleting the main inode.
-	 */
-	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
-	if (err) {
-		ext4_warning(inode->i_sb,
-			     "couldn't delete inode's xattr (err %d)", err);
-		goto stop_handle;
-	}
-
-	if (!IS_NOQUOTA(inode))
-		extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-	if (!ext4_handle_has_enough_credits(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits)) {
-		err = ext4_journal_extend(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-			goto stop_handle;
-		}
-	}
-
 	inode->i_size = 0;
 	err = ext4_mark_inode_dirty(handle, inode);
 	if (err) {
@@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode)
 		}
 	}
 
-	/*
-	 * ext4_ext_truncate() doesn't reserve any slop when it
-	 * restarts journal transactions; therefore there may not be
-	 * enough credits left in the handle to remove the inode from
-	 * the orphan list and set the dtime field.
-	 */
-	if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
-		err = ext4_journal_extend(handle, extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle, extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-		stop_handle:
-			ext4_journal_stop(handle);
-			ext4_orphan_del(NULL, inode);
-			sb_end_intwrite(inode->i_sb);
-			goto no_delete;
-		}
+	/* Remove xattr references. */
+	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+				      extra_credits);
+	if (err) {
+		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+	stop_handle:
+		ext4_journal_stop(handle);
+		ext4_orphan_del(NULL, inode);
+		sb_end_intwrite(inode->i_sb);
+		ext4_xattr_inode_array_free(ea_inode_array);
+		goto no_delete;
 	}
 
 	/*
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode)
 		ext4_clear_inode(inode);
 	else
 		ext4_free_inode(handle, inode);
-
 	ext4_journal_stop(handle);
 	sb_end_intwrite(inode->i_sb);
 	ext4_xattr_inode_array_free(ea_inode_array);
fs/ext4/xattr.c +164 -93

311 lines not on this page · raw message

fs/ext4/xattr.h +2 -1
index adf761518a73..b2005a2716d9 100644
@@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-				   struct ext4_xattr_inode_array **array);
+				   struct ext4_xattr_inode_array **array,
+				   int extra_credits);
 extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
Signature · 1 line
2.13.1.508.gb3defc5cc-goog
#41 lore raw

Re: [PATCH v2 26/28] ext4: cleanup transaction restarts during inode deletion

Quoted 11 lines · Tahsin Erdogan

During inode deletion, journal credits that will be needed are hard to determine, that is why we have journal extend/restart calls in several places. Whenever a transaction is restarted, filesystem must be in a consistent state because there is no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of journal extend/restart logic. It also handles getting jbd2 write access and dirty metadata calls. This function is called at every iteration of handling an ea_inode reference.

Another option that might be less complex is to just add the xattr inodes to the orphan list in the main transaction (which should be a fixed number of credits), and then truncate/unlink the xattr inodes after the main transaction has completed rather than making the transactions arbitrarily large. At one point we even had a separate unlink thread to handle this in the background to reduce the unlink latency for very large files, which also avoids issues with nested transactions.

Cheers, Andreas

Quoted 445 lines

---
v2: made ext4_xattr_ensure_credits() static

fs/ext4/inode.c |  66 ++++-----------
fs/ext4/xattr.c | 257 ++++++++++++++++++++++++++++++++++++--------------------
fs/ext4/xattr.h |   3 +-
3 files changed, 183 insertions(+), 143 deletions(-)
fs/ext4/inode.c +17 -49
index cf91532765a4..4d6936f0d8a4 100644
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode)
 	 */
 	sb_start_intwrite(inode->i_sb);
 
-	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
+	if (!IS_NOQUOTA(inode))
+		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+				 ext4_blocks_for_truncate(inode)+extra_credits);
 	if (IS_ERR(handle)) {
 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode)
 		sb_end_intwrite(inode->i_sb);
 		goto no_delete;
 	}
+
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);
-
-	/*
-	 * Delete xattr inode before deleting the main inode.
-	 */
-	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
-	if (err) {
-		ext4_warning(inode->i_sb,
-			     "couldn't delete inode's xattr (err %d)", err);
-		goto stop_handle;
-	}
-
-	if (!IS_NOQUOTA(inode))
-		extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-	if (!ext4_handle_has_enough_credits(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits)) {
-		err = ext4_journal_extend(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-			goto stop_handle;
-		}
-	}
-
 	inode->i_size = 0;
 	err = ext4_mark_inode_dirty(handle, inode);
 	if (err) {
@@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode)
 		}
 	}
 
-	/*
-	 * ext4_ext_truncate() doesn't reserve any slop when it
-	 * restarts journal transactions; therefore there may not be
-	 * enough credits left in the handle to remove the inode from
-	 * the orphan list and set the dtime field.
-	 */
-	if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
-		err = ext4_journal_extend(handle, extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle, extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-		stop_handle:
-			ext4_journal_stop(handle);
-			ext4_orphan_del(NULL, inode);
-			sb_end_intwrite(inode->i_sb);
-			goto no_delete;
-		}
+	/* Remove xattr references. */
+	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+				      extra_credits);
+	if (err) {
+		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+	stop_handle:
+		ext4_journal_stop(handle);
+		ext4_orphan_del(NULL, inode);
+		sb_end_intwrite(inode->i_sb);
+		ext4_xattr_inode_array_free(ea_inode_array);
+		goto no_delete;
 	}
 
 	/*
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode)
 		ext4_clear_inode(inode);
 	else
 		ext4_free_inode(handle, inode);
-
 	ext4_journal_stop(handle);
 	sb_end_intwrite(inode->i_sb);
 	ext4_xattr_inode_array_free(ea_inode_array);
fs/ext4/xattr.c +125 -36
index 3ee7e2f68476..abc7d5f84e5f 100644
@@ -108,6 +108,10 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 #define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
 				inode->i_sb->s_fs_info)->s_mb_cache)
 
+static int
+ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
+			struct inode *inode);
+
 #ifdef CONFIG_LOCKDEP
 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 {
@@ -653,6 +657,127 @@ static void ext4_xattr_update_super_block(handle_t *handle,
 	}
 }
 
+static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
+				     int credits, struct buffer_head *bh,
+				     bool dirty, bool block_csum)
+{
+	int error;
+
+	if (!ext4_handle_valid(handle))
+		return 0;
+
+	if (handle->h_buffer_credits >= credits)
+		return 0;
+
+	error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
+	if (!error)
+		return 0;
+	if (error < 0) {
+		ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
+		return error;
+	}
+
+	if (bh && dirty) {
+		if (block_csum)
+			ext4_xattr_block_csum_set(inode, bh);
+		error = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (error) {
+			ext4_warning(inode->i_sb, "Handle metadata (error %d)",
+				     error);
+			return error;
+		}
+	}
+
+	error = ext4_journal_restart(handle, credits);
+	if (error) {
+		ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
+		return error;
+	}
+
+	if (bh) {
+		error = ext4_journal_get_write_access(handle, bh);
+		if (error) {
+			ext4_warning(inode->i_sb,
+				     "Get write access failed (error %d)",
+				     error);
+			return error;
+		}
+	}
+	return 0;
+}
+
+static void
+ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
+			    struct buffer_head *bh,
+			    struct ext4_xattr_entry *first, bool block_csum,
+			    struct ext4_xattr_inode_array **ea_inode_array,
+			    int extra_credits)
+{
+	struct inode *ea_inode;
+	struct ext4_xattr_entry *entry;
+	bool dirty = false;
+	unsigned int ea_ino;
+	int err;
+	int credits;
+
+	/* One credit for dec ref on ea_inode, one for orphan list addition, */
+	credits = 2 + extra_credits;
+
+	for (entry = first; !IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+		if (err)
+			continue;
+
+		err = ext4_expand_inode_array(ea_inode_array, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode,
+					   "Expand inode array err=%d", err);
+			iput(ea_inode);
+			continue;
+		}
+
+		err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
+						dirty, block_csum);
+		if (err) {
+			ext4_warning_inode(ea_inode, "Ensure credits err=%d",
+					   err);
+			continue;
+		}
+
+		inode_lock(ea_inode);
+		clear_nlink(ea_inode);
+		ext4_orphan_add(handle, ea_inode);
+		inode_unlock(ea_inode);
+
+		/*
+		 * Forget about ea_inode within the same transaction that decrements the ref
+		 * count. This avoids duplicate decrements in case the rest of the work
+		 * spills over to subsequent transactions.
+		 */
+		entry->e_value_inum = 0;
+		entry->e_value_size = 0;
+
+		dirty = true;
+	}
+
+	if (dirty) {
+		/*
+		 * Note that we are deliberately skipping csum calculation for
+		 * the final update because we do not expect any journal
+		 * restarts until xattr block is freed.
+		 */
+
+		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		if (err)
+			ext4_warning_inode(parent,
+					   "handle dirty metadata err=%d", err);
+	}
+}
+
 /*
 * Release the xattr block BH: If the reference count is > 1, decrement it;
 * otherwise free the block.
@@ -1985,42 +2110,6 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 	return 0;
 }
 
-/**
- * Add xattr inode to orphan list
- */
-static int
-ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits,
-			    struct ext4_xattr_inode_array *ea_inode_array)
-{
-	int idx = 0, error = 0;
-	struct inode *ea_inode;
-
-	if (ea_inode_array == NULL)
-		return 0;
-
-	for (; idx < ea_inode_array->count; ++idx) {
-		if (!ext4_handle_has_enough_credits(handle, credits)) {
-			error = ext4_journal_extend(handle, credits);
-			if (error > 0)
-				error = ext4_journal_restart(handle, credits);
-
-			if (error != 0) {
-				ext4_warning(inode->i_sb,
-					"couldn't extend journal "
-					"(err %d)", error);
-				return error;
-			}
-		}
-		ea_inode = ea_inode_array->inodes[idx];
-		inode_lock(ea_inode);
-		ext4_orphan_add(handle, ea_inode);
-		inode_unlock(ea_inode);
-		/* the inode's i_count will be released by caller */
-	}
-
-	return 0;
-}
-
 /*
 * ext4_xattr_delete_inode()
 *
@@ -2033,16 +2122,23 @@ ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits,
 */

int
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,

fs/ext4/xattr.c +2 -1
-			struct ext4_xattr_inode_array **ea_inode_array)
+			struct ext4_xattr_inode_array **ea_inode_array,
+			int extra_credits)
{
	struct buffer_head *bh = NULL;
	struct ext4_xattr_ibody_header *header;
	struct ext4_inode *raw_inode;
fs/ext4/xattr.c +11 -5
-	struct ext4_iloc iloc;
-	struct ext4_xattr_entry *entry;
-	struct inode *ea_inode;
-	unsigned int ea_ino;
-	int credits = 3, error = 0;
+	struct ext4_iloc iloc = { .bh = NULL };
+	int error;
+
+	error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
+					  NULL /* bh */,
+					  false /* dirty */,
+					  false /* block_csum */);
+	if (error) {
+		EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
+		goto cleanup;
+	}
	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
		goto delete_external_ea;
fs/ext4/xattr.c +8 -17
@@ -2050,31 +2146,20 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 	error = ext4_get_inode_loc(inode, &iloc);
 	if (error)
 		goto cleanup;
+
+	error = ext4_journal_get_write_access(handle, iloc.bh);
+	if (error)
+		goto cleanup;
+
 	raw_inode = ext4_raw_inode(&iloc);
 	header = IHDR(inode, raw_inode);
-	for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
-	     entry = EXT4_XATTR_NEXT(entry)) {
-		if (!entry->e_value_inum)
-			continue;
-		ea_ino = le32_to_cpu(entry->e_value_inum);
-		error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-		if (error)
-			continue;
-		error = ext4_expand_inode_array(ea_inode_array, ea_inode);
-		if (error) {
-			iput(ea_inode);
-			brelse(iloc.bh);
-			goto cleanup;
-		}
-		entry->e_value_inum = 0;
-	}
-	brelse(iloc.bh);
+	ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),
+				    false /* block_csum */, ea_inode_array,
+				    extra_credits);
 

delete_external_ea:

	if (!EXT4_I(inode)->i_file_acl) {
fs/ext4/xattr.c +1 -3
-		/* add xattr inode to orphan list */
-		error = ext4_xattr_inode_orphan_add(handle, inode, credits,
-						    *ea_inode_array);
+		error = 0;
		goto cleanup;
	}
	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
fs/ext4/xattr.c +16 -30
@@ -2092,46 +2177,32 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 		goto cleanup;
 	}
 
-	for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
-	     entry = EXT4_XATTR_NEXT(entry)) {
-		if (!entry->e_value_inum)
-			continue;
-		ea_ino = le32_to_cpu(entry->e_value_inum);
-		error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-		if (error)
-			continue;
-		error = ext4_expand_inode_array(ea_inode_array, ea_inode);
-		if (error)
-			goto cleanup;
-		entry->e_value_inum = 0;
-	}
-
-	/* add xattr inode to orphan list */
-	error = ext4_xattr_inode_orphan_add(handle, inode, credits,
-					*ea_inode_array);
-	if (error)
-		goto cleanup;
-
-	if (!IS_NOQUOTA(inode))
-		credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-	if (!ext4_handle_has_enough_credits(handle, credits)) {
-		error = ext4_journal_extend(handle, credits);
-		if (error > 0)
-			error = ext4_journal_restart(handle, credits);
+	if (ext4_has_feature_ea_inode(inode->i_sb)) {
+		error = ext4_journal_get_write_access(handle, bh);
 		if (error) {
-			ext4_warning(inode->i_sb,
-				"couldn't extend journal (err %d)", error);
+			EXT4_ERROR_INODE(inode, "write access %llu",
+					 EXT4_I(inode)->i_file_acl);
 			goto cleanup;
 		}
+		ext4_xattr_inode_remove_all(handle, inode, bh,
+					    BFIRST(bh),
+					    true /* block_csum */,
+					    ea_inode_array,
+					    extra_credits);
 	}
 
 	ext4_xattr_release_block(handle, inode, bh);
+	/* Update i_file_acl within the same transaction that releases block. */
 	EXT4_I(inode)->i_file_acl = 0;
-
+	error = ext4_mark_inode_dirty(handle, inode);
+	if (error) {
+		EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+				 error);
+		goto cleanup;
+	}

cleanup:

fs/ext4/xattr.c +1 -0
+	brelse(iloc.bh);
	brelse(bh);
-
	return error;
}
fs/ext4/xattr.h +2 -2
index adf761518a73..b2005a2716d9 100644
@@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-				   struct ext4_xattr_inode_array **array);
+				   struct ext4_xattr_inode_array **array,
+				   int extra_credits);
 extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
--
Quoted 2 lines

2.13.1.508.gb3defc5cc-goog

Cheers, Andreas

#42 lore raw

PATCH v3 26/28 ext4: cleanup transaction restarts during inode deletion

During inode deletion, journal credits that will be needed are hard to determine, that is why we have journal extend/restart calls in several places. Whenever a transaction is restarted, filesystem must be in a consistent state because there is no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of journal extend/restart logic. It also handles getting jbd2 write access and dirty metadata calls. This function is called at every iteration of handling an ea_inode reference.

---
v3: fixed checkpatch.pl warnings about long lines and indented label

v2: made ext4_xattr_ensure_credits() static

 fs/ext4/inode.c |  66 ++++-----------
 fs/ext4/xattr.c | 258 ++++++++++++++++++++++++++++++++++++--------------------
 fs/ext4/xattr.h |   3 +-
 3 files changed, 184 insertions(+), 143 deletions(-)
fs/ext4/inode.c +17 -49
index cf91532765a4..cd007f9757d1 100644
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode)
 	 */
 	sb_start_intwrite(inode->i_sb);
 
-	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
+	if (!IS_NOQUOTA(inode))
+		extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+				 ext4_blocks_for_truncate(inode)+extra_credits);
 	if (IS_ERR(handle)) {
 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode)
 		sb_end_intwrite(inode->i_sb);
 		goto no_delete;
 	}
+
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);
-
-	/*
-	 * Delete xattr inode before deleting the main inode.
-	 */
-	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
-	if (err) {
-		ext4_warning(inode->i_sb,
-			     "couldn't delete inode's xattr (err %d)", err);
-		goto stop_handle;
-	}
-
-	if (!IS_NOQUOTA(inode))
-		extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-	if (!ext4_handle_has_enough_credits(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits)) {
-		err = ext4_journal_extend(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle,
-			ext4_blocks_for_truncate(inode) + extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-			goto stop_handle;
-		}
-	}
-
 	inode->i_size = 0;
 	err = ext4_mark_inode_dirty(handle, inode);
 	if (err) {
@@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode)
 		}
 	}
 
-	/*
-	 * ext4_ext_truncate() doesn't reserve any slop when it
-	 * restarts journal transactions; therefore there may not be
-	 * enough credits left in the handle to remove the inode from
-	 * the orphan list and set the dtime field.
-	 */
-	if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
-		err = ext4_journal_extend(handle, extra_credits);
-		if (err > 0)
-			err = ext4_journal_restart(handle, extra_credits);
-		if (err != 0) {
-			ext4_warning(inode->i_sb,
-				     "couldn't extend journal (err %d)", err);
-		stop_handle:
-			ext4_journal_stop(handle);
-			ext4_orphan_del(NULL, inode);
-			sb_end_intwrite(inode->i_sb);
-			goto no_delete;
-		}
+	/* Remove xattr references. */
+	err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+				      extra_credits);
+	if (err) {
+		ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+stop_handle:
+		ext4_journal_stop(handle);
+		ext4_orphan_del(NULL, inode);
+		sb_end_intwrite(inode->i_sb);
+		ext4_xattr_inode_array_free(ea_inode_array);
+		goto no_delete;
 	}
 
 	/*
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode)
 		ext4_clear_inode(inode);
 	else
 		ext4_free_inode(handle, inode);
-
 	ext4_journal_stop(handle);
 	sb_end_intwrite(inode->i_sb);
 	ext4_xattr_inode_array_free(ea_inode_array);
fs/ext4/xattr.c +165 -93

312 lines not on this page · raw message

fs/ext4/xattr.h +2 -1
index adf761518a73..b2005a2716d9 100644
@@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-				   struct ext4_xattr_inode_array **array);
+				   struct ext4_xattr_inode_array **array,
+				   int extra_credits);
 extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
Signature · 1 line
2.13.1.518.g3df882009-goog
#43 lore raw

Re: [PATCH v3 26/28] ext4: cleanup transaction restarts during inode deletion

Quoted 7 lines · Andreas Dilger

Another option that might be less complex is to just add the xattr inodes to the orphan list in the main transaction (which should be a fixed number of credits), and then truncate/unlink the xattr inodes after the main transaction has completed rather than making the transactions arbitrarily large. At one point we even had a separate unlink thread to handle this in the background to reduce the unlink latency for very large files, which also avoids issues with nested transactions.

I think that is true for simple xattr value updates or removals, but when we delete the parent inode we have to drop references to all xattr inodes which again becomes arbitrarily large. Also with deduplication patch that follows, dropping xattr inode reference does not always cause deletion of the inode so I am not sure whether that version can be simplified.

Quoted 461 lines · Tahsin Erdogan

During inode deletion, journal credits that will be needed are hard to determine, that is why we have journal extend/restart calls in several places. Whenever a transaction is restarted, filesystem must be in a consistent state because there is no atomicity guarantee beyond a restart call.

Add ext4_xattr_ensure_credits() helper function which takes care of journal extend/restart logic. It also handles getting jbd2 write access and dirty metadata calls. This function is called at every iteration of handling an ea_inode reference.

---
v3: fixed checkpatch.pl warnings about long lines and indented label

v2: made ext4_xattr_ensure_credits() static

 fs/ext4/inode.c |  66 ++++-----------
 fs/ext4/xattr.c | 258 ++++++++++++++++++++++++++++++++++++--------------------
 fs/ext4/xattr.h |   3 +-
 3 files changed, 184 insertions(+), 143 deletions(-)
fs/ext4/inode.c +17 -49
index cf91532765a4..cd007f9757d1 100644
@@ -239,7 +239,11 @@ void ext4_evict_inode(struct inode *inode)
         */
        sb_start_intwrite(inode->i_sb);
 
-       handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
+       if (!IS_NOQUOTA(inode))
+               extra_credits += EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb);
+
+       handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
+                                ext4_blocks_for_truncate(inode)+extra_credits);
        if (IS_ERR(handle)) {
                ext4_std_error(inode->i_sb, PTR_ERR(handle));
                /*
@@ -251,36 +255,9 @@ void ext4_evict_inode(struct inode *inode)
                sb_end_intwrite(inode->i_sb);
                goto no_delete;
        }
+
        if (IS_SYNC(inode))
                ext4_handle_sync(handle);
-
-       /*
-        * Delete xattr inode before deleting the main inode.
-        */
-       err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array);
-       if (err) {
-               ext4_warning(inode->i_sb,
-                            "couldn't delete inode's xattr (err %d)", err);
-               goto stop_handle;
-       }
-
-       if (!IS_NOQUOTA(inode))
-               extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-       if (!ext4_handle_has_enough_credits(handle,
-                       ext4_blocks_for_truncate(inode) + extra_credits)) {
-               err = ext4_journal_extend(handle,
-                       ext4_blocks_for_truncate(inode) + extra_credits);
-               if (err > 0)
-                       err = ext4_journal_restart(handle,
-                       ext4_blocks_for_truncate(inode) + extra_credits);
-               if (err != 0) {
-                       ext4_warning(inode->i_sb,
-                                    "couldn't extend journal (err %d)", err);
-                       goto stop_handle;
-               }
-       }
-
        inode->i_size = 0;
        err = ext4_mark_inode_dirty(handle, inode);
        if (err) {
@@ -298,25 +275,17 @@ void ext4_evict_inode(struct inode *inode)
                }
        }
 
-       /*
-        * ext4_ext_truncate() doesn't reserve any slop when it
-        * restarts journal transactions; therefore there may not be
-        * enough credits left in the handle to remove the inode from
-        * the orphan list and set the dtime field.
-        */
-       if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
-               err = ext4_journal_extend(handle, extra_credits);
-               if (err > 0)
-                       err = ext4_journal_restart(handle, extra_credits);
-               if (err != 0) {
-                       ext4_warning(inode->i_sb,
-                                    "couldn't extend journal (err %d)", err);
-               stop_handle:
-                       ext4_journal_stop(handle);
-                       ext4_orphan_del(NULL, inode);
-                       sb_end_intwrite(inode->i_sb);
-                       goto no_delete;
-               }
+       /* Remove xattr references. */
+       err = ext4_xattr_delete_inode(handle, inode, &ea_inode_array,
+                                     extra_credits);
+       if (err) {
+               ext4_warning(inode->i_sb, "xattr delete (err %d)", err);
+stop_handle:
+               ext4_journal_stop(handle);
+               ext4_orphan_del(NULL, inode);
+               sb_end_intwrite(inode->i_sb);
+               ext4_xattr_inode_array_free(ea_inode_array);
+               goto no_delete;
        }
 
        /*
@@ -342,7 +311,6 @@ void ext4_evict_inode(struct inode *inode)
                ext4_clear_inode(inode);
        else
                ext4_free_inode(handle, inode);
-
        ext4_journal_stop(handle);
        sb_end_intwrite(inode->i_sb);
        ext4_xattr_inode_array_free(ea_inode_array);
fs/ext4/xattr.c +165 -93
index e69550e23d64..0484df8dadd1 100644
@@ -108,6 +108,10 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 #define EXT4_GET_MB_CACHE(inode)       (((struct ext4_sb_info *) \
                                inode->i_sb->s_fs_info)->s_mb_cache)
 
+static int
+ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
+                       struct inode *inode);
+
 #ifdef CONFIG_LOCKDEP
 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 {
@@ -653,6 +657,128 @@ static void ext4_xattr_update_super_block(handle_t *handle,
        }
 }
 
+static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
+                                    int credits, struct buffer_head *bh,
+                                    bool dirty, bool block_csum)
+{
+       int error;
+
+       if (!ext4_handle_valid(handle))
+               return 0;
+
+       if (handle->h_buffer_credits >= credits)
+               return 0;
+
+       error = ext4_journal_extend(handle, credits - handle->h_buffer_credits);
+       if (!error)
+               return 0;
+       if (error < 0) {
+               ext4_warning(inode->i_sb, "Extend journal (error %d)", error);
+               return error;
+       }
+
+       if (bh && dirty) {
+               if (block_csum)
+                       ext4_xattr_block_csum_set(inode, bh);
+               error = ext4_handle_dirty_metadata(handle, NULL, bh);
+               if (error) {
+                       ext4_warning(inode->i_sb, "Handle metadata (error %d)",
+                                    error);
+                       return error;
+               }
+       }
+
+       error = ext4_journal_restart(handle, credits);
+       if (error) {
+               ext4_warning(inode->i_sb, "Restart journal (error %d)", error);
+               return error;
+       }
+
+       if (bh) {
+               error = ext4_journal_get_write_access(handle, bh);
+               if (error) {
+                       ext4_warning(inode->i_sb,
+                                    "Get write access failed (error %d)",
+                                    error);
+                       return error;
+               }
+       }
+       return 0;
+}
+
+static void
+ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
+                           struct buffer_head *bh,
+                           struct ext4_xattr_entry *first, bool block_csum,
+                           struct ext4_xattr_inode_array **ea_inode_array,
+                           int extra_credits)
+{
+       struct inode *ea_inode;
+       struct ext4_xattr_entry *entry;
+       bool dirty = false;
+       unsigned int ea_ino;
+       int err;
+       int credits;
+
+       /* One credit for dec ref on ea_inode, one for orphan list addition, */
+       credits = 2 + extra_credits;
+
+       for (entry = first; !IS_LAST_ENTRY(entry);
+            entry = EXT4_XATTR_NEXT(entry)) {
+               if (!entry->e_value_inum)
+                       continue;
+               ea_ino = le32_to_cpu(entry->e_value_inum);
+               err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+               if (err)
+                       continue;
+
+               err = ext4_expand_inode_array(ea_inode_array, ea_inode);
+               if (err) {
+                       ext4_warning_inode(ea_inode,
+                                          "Expand inode array err=%d", err);
+                       iput(ea_inode);
+                       continue;
+               }
+
+               err = ext4_xattr_ensure_credits(handle, parent, credits, bh,
+                                               dirty, block_csum);
+               if (err) {
+                       ext4_warning_inode(ea_inode, "Ensure credits err=%d",
+                                          err);
+                       continue;
+               }
+
+               inode_lock(ea_inode);
+               clear_nlink(ea_inode);
+               ext4_orphan_add(handle, ea_inode);
+               inode_unlock(ea_inode);
+
+               /*
+                * Forget about ea_inode within the same transaction that
+                * decrements the ref count. This avoids duplicate decrements in
+                * case the rest of the work spills over to subsequent
+                * transactions.
+                */
+               entry->e_value_inum = 0;
+               entry->e_value_size = 0;
+
+               dirty = true;
+       }
+
+       if (dirty) {
+               /*
+                * Note that we are deliberately skipping csum calculation for
+                * the final update because we do not expect any journal
+                * restarts until xattr block is freed.
+                */
+
+               err = ext4_handle_dirty_metadata(handle, NULL, bh);
+               if (err)
+                       ext4_warning_inode(parent,
+                                          "handle dirty metadata err=%d", err);
+       }
+}
+
 /*
  * Release the xattr block BH: If the reference count is > 1, decrement it;
  * otherwise free the block.
@@ -1985,42 +2111,6 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
        return 0;
 }
 
-/**
- * Add xattr inode to orphan list
- */
-static int
-ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits,
-                           struct ext4_xattr_inode_array *ea_inode_array)
-{
-       int idx = 0, error = 0;
-       struct inode *ea_inode;
-
-       if (ea_inode_array == NULL)
-               return 0;
-
-       for (; idx < ea_inode_array->count; ++idx) {
-               if (!ext4_handle_has_enough_credits(handle, credits)) {
-                       error = ext4_journal_extend(handle, credits);
-                       if (error > 0)
-                               error = ext4_journal_restart(handle, credits);
-
-                       if (error != 0) {
-                               ext4_warning(inode->i_sb,
-                                       "couldn't extend journal "
-                                       "(err %d)", error);
-                               return error;
-                       }
-               }
-               ea_inode = ea_inode_array->inodes[idx];
-               inode_lock(ea_inode);
-               ext4_orphan_add(handle, ea_inode);
-               inode_unlock(ea_inode);
-               /* the inode's i_count will be released by caller */
-       }
-
-       return 0;
-}
-
 /*
  * ext4_xattr_delete_inode()
  *
@@ -2033,16 +2123,23 @@ ext4_xattr_inode_orphan_add(handle_t *handle, struct inode *inode, int credits,
  */
 int
 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-                       struct ext4_xattr_inode_array **ea_inode_array)
+                       struct ext4_xattr_inode_array **ea_inode_array,
+                       int extra_credits)
 {
        struct buffer_head *bh = NULL;
        struct ext4_xattr_ibody_header *header;
        struct ext4_inode *raw_inode;
-       struct ext4_iloc iloc;
-       struct ext4_xattr_entry *entry;
-       struct inode *ea_inode;
-       unsigned int ea_ino;
-       int credits = 3, error = 0;
+       struct ext4_iloc iloc = { .bh = NULL };
+       int error;
+
+       error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
+                                         NULL /* bh */,
+                                         false /* dirty */,
+                                         false /* block_csum */);
+       if (error) {
+               EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error);
+               goto cleanup;
+       }
 
        if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
                goto delete_external_ea;
@@ -2050,31 +2147,20 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
        error = ext4_get_inode_loc(inode, &iloc);
        if (error)
                goto cleanup;
+
+       error = ext4_journal_get_write_access(handle, iloc.bh);
+       if (error)
+               goto cleanup;
+
        raw_inode = ext4_raw_inode(&iloc);
        header = IHDR(inode, raw_inode);
-       for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
-            entry = EXT4_XATTR_NEXT(entry)) {
-               if (!entry->e_value_inum)
-                       continue;
-               ea_ino = le32_to_cpu(entry->e_value_inum);
-               error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-               if (error)
-                       continue;
-               error = ext4_expand_inode_array(ea_inode_array, ea_inode);
-               if (error) {
-                       iput(ea_inode);
-                       brelse(iloc.bh);
-                       goto cleanup;
-               }
-               entry->e_value_inum = 0;
-       }
-       brelse(iloc.bh);
+       ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),
+                                   false /* block_csum */, ea_inode_array,
+                                   extra_credits);
 
 delete_external_ea:
        if (!EXT4_I(inode)->i_file_acl) {
-               /* add xattr inode to orphan list */
-               error = ext4_xattr_inode_orphan_add(handle, inode, credits,
-                                                   *ea_inode_array);
+               error = 0;
                goto cleanup;
        }
        bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
@@ -2092,46 +2178,32 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
                goto cleanup;
        }
 
-       for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
-            entry = EXT4_XATTR_NEXT(entry)) {
-               if (!entry->e_value_inum)
-                       continue;
-               ea_ino = le32_to_cpu(entry->e_value_inum);
-               error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-               if (error)
-                       continue;
-               error = ext4_expand_inode_array(ea_inode_array, ea_inode);
-               if (error)
-                       goto cleanup;
-               entry->e_value_inum = 0;
-       }
-
-       /* add xattr inode to orphan list */
-       error = ext4_xattr_inode_orphan_add(handle, inode, credits,
-                                       *ea_inode_array);
-       if (error)
-               goto cleanup;
-
-       if (!IS_NOQUOTA(inode))
-               credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
-
-       if (!ext4_handle_has_enough_credits(handle, credits)) {
-               error = ext4_journal_extend(handle, credits);
-               if (error > 0)
-                       error = ext4_journal_restart(handle, credits);
+       if (ext4_has_feature_ea_inode(inode->i_sb)) {
+               error = ext4_journal_get_write_access(handle, bh);
                if (error) {
-                       ext4_warning(inode->i_sb,
-                               "couldn't extend journal (err %d)", error);
+                       EXT4_ERROR_INODE(inode, "write access %llu",
+                                        EXT4_I(inode)->i_file_acl);
                        goto cleanup;
                }
+               ext4_xattr_inode_remove_all(handle, inode, bh,
+                                           BFIRST(bh),
+                                           true /* block_csum */,
+                                           ea_inode_array,
+                                           extra_credits);
        }
 
        ext4_xattr_release_block(handle, inode, bh);
+       /* Update i_file_acl within the same transaction that releases block. */
        EXT4_I(inode)->i_file_acl = 0;
-
+       error = ext4_mark_inode_dirty(handle, inode);
+       if (error) {
+               EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+                                error);
+               goto cleanup;
+       }
 cleanup:
+       brelse(iloc.bh);
        brelse(bh);
-
        return error;
 }
 
fs/ext4/xattr.h +2 -2
index adf761518a73..b2005a2716d9 100644
@@ -169,7 +169,8 @@ extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
 
 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-                                  struct ext4_xattr_inode_array **array);
+                                  struct ext4_xattr_inode_array **array,
+                                  int extra_credits);
 extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
 
 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
--

2.13.1.518.g3df882009-goog

#44 lore raw

PATCH 27/28 ext4: xattr inode deduplication

In reply to Tahsin Erdogan

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |    7 +-
 fs/ext4/inode.c |    9 +-
 fs/ext4/super.c |   22 +-
 fs/ext4/xattr.c | 1073 +++++++++++++++++++++++++++++++++++++++++++------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 881 insertions(+), 261 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +6 -1
index d79d8d7bee88..79f06290e723 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
fs/ext4/inode.c +8 -1
index 4d6936f0d8a4..6f5872197d6c 100644
@@ -4843,8 +4843,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/super.c +21 -1
index b02a23ec92ca..7d2b692d52ea 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -4067,6 +4074,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4312,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +835 -238

1,364 lines not on this page · raw message

fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -70,19 +70,6 @@ struct ext4_xattr_entry {
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
 /*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
-/*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
 */
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 77a5b99d8f92..7dfdca822ccb 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#45 lore raw

Re: [PATCH 27/28] ext4: xattr inode deduplication

reproduce: wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree make.cross…

Hi Tahsin,

[auto build test ERROR on ext4/dev]
[also build test ERROR on next-20170531]
[cannot apply to v4.12-rc3]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Tahsin-Erdogan/ext4-xattr-in-inode-support/20170531-214310
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
config: powerpc-pcm030_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705

reproduce:
wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=powerpc

All errors (new ones prefixed by >>):

>> ERROR: "crc32c" [fs/ext4/ext4.ko] undefined!

---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation

#46 lore raw

Re: [PATCH 27/28] ext4: xattr inode deduplication

In reply to Tahsin Erdogan
reproduce:

Hi Tahsin,

[auto build test ERROR on ext4/dev]
[also build test ERROR on next-20170531]
[cannot apply to v4.12-rc3]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Tahsin-Erdogan/ext4-xattr-in-inode-support/20170531-214310
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
config: i386-defconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

fs/built-in.o: In function `ext4_xattr_inode_get':

>> xattr.c:(.text+0xb8818): undefined reference to `crc32c'

fs/built-in.o: In function `ext4_xattr_set_entry':
xattr.c:(.text+0xb9614): undefined reference to `crc32c'

---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation

#47 lore raw

Re: [PATCH 27/28] ext4: xattr inode deduplication

In reply to Tahsin Erdogan
Quoted 208 lines · Tahsin Erdogan

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |    7 +-
 fs/ext4/inode.c |    9 +-
 fs/ext4/super.c |   22 +-
 fs/ext4/xattr.c | 1073 +++++++++++++++++++++++++++++++++++++++++++------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 881 insertions(+), 261 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +6 -1
index d79d8d7bee88..79f06290e723 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
fs/ext4/inode.c +8 -1
index 4d6936f0d8a4..6f5872197d6c 100644
@@ -4843,8 +4843,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/super.c +21 -1
index b02a23ec92ca..7d2b692d52ea 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -4067,6 +4074,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4312,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +12 -8
index 6acce1f689ab..caddc176a612 100644
@@ -55,6 +55,7 @@
 #include <linux/slab.h>
 #include <linux/mbcache.h>
 #include <linux/quotaops.h>
+#include <linux/crc32c.h>
 #include "ext4_jbd2.h"
 #include "ext4.h"
 #include "xattr.h"
@@ -79,6 +80,7 @@ ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
 			    struct mb_cache_entry **);
 static void ext4_xattr_rehash(struct ext4_xattr_header *,
 			      struct ext4_xattr_entry *);
+static int ext4_xattr_read_ea_hash(struct inode *ea_inode, u32 *hash);
 
 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
 	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
@@ -105,13 +107,23 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 	NULL
 };
 
+#define EXT4_XATTR_SYSTEM_EA_INFO  "eai"
+
 #define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
 				inode->i_sb->s_fs_info)->s_mb_cache)
 
+#define EA_INODE_CACHE(inode)	(((struct ext4_sb_info *) \
+				inode->i_sb->s_fs_info)->s_ea_inode_cache)
+
 static int
 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 			struct inode *inode);
 
+static int ext4_xattr_inode_init(handle_t *handle, struct inode *ea_inode,
+				 u32 hash);
+static int ext4_xattr_update_ea_info(struct inode *ea_inode, int ref_change,
+				     u64 *ref_return, u32 *hash);
+
 #ifdef CONFIG_LOCKDEP
 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 {
@@ -329,14 +341,6 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 		goto error;
 	}
 
-	if (EXT4_XATTR_INODE_GET_PARENT(inode) != parent->i_ino ||
-	    inode->i_generation != parent->i_generation) {
-		ext4_error(parent->i_sb, "Backpointer from EA inode %lu "
-			   "to parent is invalid.", ea_ino);
-		err = -EINVAL;
-		goto error;
-	}
-
 	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 		ext4_error(parent->i_sb, "EA inode %lu does not have "
 			   "EXT4_EA_INODE_FL flag set.\n", ea_ino);

fs/ext4/xattr.c static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino, · line 360

Quoted 6 lines
fs/ext4/xattr.c +3 -0
@@ -351,6 +355,11 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 	return err;
 }
 
+static u32 ext4_xattr_inode_hash(const void *buffer, size_t size)
+{
+	return crc32c(0, buffer, size);

The metadata checksumming code uses crypto_alloc_shash to dynamically bind to the crc32c implementation only when ext4 actually needs it. This introduces a static module dependency on libcrc32c even though we only need it if we're deduplicating xattrs, which is done only when EXT4_FEATURE_INCOMPAT_EA_INODE is enabled, correct?

Or, looking through the code, maybe not; are we now capable of deduping for any filesystem?

Anyway, if this dedupe feature is hidden behind INCOMPAT_EA_INODE then this crc32c call binding should be done dynamically; however, if it works for any filesystem and is therefore on all the time, the existing users ought to be converted to use libcrc32c.

--D

Quoted 1,391 lines
fs/ext4/xattr.c +820 -230
+}
+
 /*
  * Read the value from the EA inode.
  */
@@ -358,17 +367,52 @@ static int
 ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
 		     size_t size)
 {
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 	struct inode *ea_inode;
-	int ret;
+	u32 hash, calc_hash;
+	struct mb_cache_entry *ce;
+	int err;
 
-	ret = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-	if (ret)
-		return ret;
+	err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+	if (err) {
+		ea_inode = NULL;
+		goto out;
+	}
 
-	ret = ext4_xattr_inode_read(ea_inode, buffer, size);
-	iput(ea_inode);
+	if (i_size_read(ea_inode) != size) {
+		ext4_warning_inode(ea_inode,
+				   "ea_inode file size=%llu entry size=%zu",
+				   i_size_read(ea_inode), size);
+		err = -EFSCORRUPTED;
+		goto out;
+	}
 
-	return ret;
+	err = ext4_xattr_inode_read(ea_inode, buffer, size);
+	if (!err) {
+		if (ext4_xattr_read_ea_hash(ea_inode, &hash))
+			goto out;
+
+		/* Avoid hash calculation if already cached. */
+		ce = mb_cache_entry_get(ea_inode_cache, hash, ea_inode->i_ino);
+		if (ce) {
+			mb_cache_entry_put(ea_inode_cache, ce);
+			goto out;
+		}
+
+		calc_hash = ext4_xattr_inode_hash(buffer, size);
+		if (hash != calc_hash) {
+			ext4_warning_inode(ea_inode, "EA inode saved hash=%#x "
+					   "does not match calc_hash=%#x",
+					   hash, calc_hash);
+			goto out;
+		}
+
+		mb_cache_entry_create(ea_inode_cache, GFP_NOFS, hash,
+				      ea_inode->i_ino, true /* reusable */);
+	}
+out:
+	iput(ea_inode);
+	return err;
 }
 
 static int
@@ -657,6 +701,101 @@ static void ext4_xattr_update_super_block(handle_t *handle,
 	}
 }
 
+static inline size_t round_up_cluster(struct inode *inode, size_t length)
+{
+	struct super_block *sb = inode->i_sb;
+	size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
+				    inode->i_blkbits);
+	size_t mask = ~(cluster_size - 1);
+
+	return (length + cluster_size - 1) & mask;
+}
+
+static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
+{
+	int err;
+
+	err = dquot_alloc_inode(inode);
+	if (err)
+		return err;
+	err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
+	if (err)
+		dquot_free_inode(inode);
+	return err;
+}
+
+static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
+{
+	dquot_free_space_nodirty(inode, round_up_cluster(inode, len));
+	dquot_free_inode(inode);
+}
+
+static int __ext4_xattr_set_credits(struct super_block *sb,
+				    struct buffer_head *block_bh,
+				    size_t value_len)
+{
+	int credits;
+	int blocks;
+
+	/*
+	 * 1) Owner inode update
+	 * 2) Ref count update on old xattr block
+	 * 3) new xattr block
+	 * 4) block bitmap update for new xattr block
+	 * 5) group descriptor for new xattr block
+	 */
+	credits = 5;
+
+	/* We are done if ea_inode feature is not enabled. */
+	if (!ext4_has_feature_ea_inode(sb))
+		return credits;
+
+	/* New ea_inode, inode map, block bitmap, group descriptor. */
+	credits += 4;
+
+	/* Data blocks. */
+	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+
+	/* Indirection block. */
+	blocks += 1;
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Blocks themselves. */
+	credits += blocks;
+
+	/* Dereference ea_inode holding old xattr value.
+	 * Old ea_inode, inode map, block bitmap, group descriptor.
+	 */
+	credits += 4;
+
+	/* Data blocks for old ea_inode. */
+	blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+
+	/* Indirection block for old ea_inode. */
+	blocks += 1;
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Quota updates. */
+	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
+
+	/* We may need to clone the existing xattr block in which case we need
+	 * to increment ref counts for existing ea_inodes referenced by it.
+	 */
+	if (block_bh) {
+		struct ext4_xattr_entry *entry = BFIRST(block_bh);
+
+		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				/* Ref count update on ea_inode. */
+				credits += 1;
+	}
+	return credits;
+}
+
 int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 			      int credits, struct buffer_head *bh,
 			      bool dirty, bool block_csum)
@@ -706,12 +845,139 @@ int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 	return 0;
 }
 
+static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
+				       int ref_change)
+{
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
+	struct ext4_iloc iloc;
+	s64 ref_return;
+	u32 hash;
+	int ret;
+
+	inode_lock(ea_inode);
+
+	ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
+	if (ret) {
+		iloc.bh = NULL;
+		goto out;
+	}
+
+	ret = ext4_xattr_update_ea_info(ea_inode, ref_change, &ref_return,
+					&hash);
+	if (ret)
+		goto out;
+
+	if (ref_change > 0) {
+		WARN_ONCE(ref_return <= 0, "EA inode %lu ref_return=%lld",
+			  ea_inode->i_ino, ref_return);
+
+		if (ref_return == 1) {
+			WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
+				  ea_inode->i_ino, ea_inode->i_nlink);
+
+			set_nlink(ea_inode, 1);
+			ext4_orphan_del(handle, ea_inode);
+
+			mb_cache_entry_create(ea_inode_cache, GFP_NOFS, hash,
+					      ea_inode->i_ino,
+					      true /* reusable */);
+		}
+	} else {
+		WARN_ONCE(ref_return < 0, "EA inode %lu ref_return=%lld",
+			  ea_inode->i_ino, ref_return);
+
+		if (ref_return == 0) {
+			WARN_ONCE(ea_inode->i_nlink != 1,
+				  "EA inode %lu i_nlink=%u",
+				  ea_inode->i_ino, ea_inode->i_nlink);
+
+			clear_nlink(ea_inode);
+			ext4_orphan_add(handle, ea_inode);
+
+			mb_cache_entry_delete(ea_inode_cache, hash,
+					      ea_inode->i_ino);
+		}
+	}
+
+	ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
+	iloc.bh = NULL;
+	if (ret)
+		ext4_warning_inode(ea_inode,
+				   "ext4_mark_iloc_dirty() failed ret=%d", ret);
+out:
+	brelse(iloc.bh);
+	inode_unlock(ea_inode);
+	return ret;
+}
+
+static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
+{
+	return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
+}
+
+static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
+{
+	return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
+}
+
+static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
+					struct ext4_xattr_entry *first)
+{
+	struct inode *ea_inode;
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_entry *failed_entry;
+	unsigned int ea_ino;
+	int err, saved_err;
+
+	for (entry = first; !IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+		if (err)
+			goto cleanup;
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode, "inc ref error %d", err);
+			iput(ea_inode);
+			goto cleanup;
+		}
+		iput(ea_inode);
+	}
+	return 0;
+
+cleanup:
+	saved_err = err;
+	failed_entry = entry;
+
+	for (entry = first; entry != failed_entry;
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+		if (err) {
+			ext4_warning(parent->i_sb,
+				     "cleanup ea_ino %u iget error %d", ea_ino,
+				     err);
+			continue;
+		}
+		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (err)
+			ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
+					   err);
+		iput(ea_inode);
+	}
+	return saved_err;
+}
+
 static void
-ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
-			    struct buffer_head *bh,
-			    struct ext4_xattr_entry *first, bool block_csum,
-			    struct ext4_xattr_inode_array **ea_inode_array,
-			    int extra_credits)
+ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
+			     struct buffer_head *bh,
+			     struct ext4_xattr_entry *first, bool block_csum,
+			     struct ext4_xattr_inode_array **ea_inode_array,
+			     int extra_credits, bool skip_quota)
 {
 	struct inode *ea_inode;
 	struct ext4_xattr_entry *entry;
@@ -748,10 +1014,16 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
 			continue;
 		}
 
-		inode_lock(ea_inode);
-		clear_nlink(ea_inode);
-		ext4_orphan_add(handle, ea_inode);
-		inode_unlock(ea_inode);
+		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
+					   err);
+			continue;
+		}
+
+		if (!skip_quota)
+			ext4_xattr_inode_free_quota(parent,
+					      le32_to_cpu(entry->e_value_size));
 
 		/*
 		 * Forget about ea_inode within the same transaction that decrements the ref
@@ -784,7 +1056,9 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
  */
 static void
 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
-			 struct buffer_head *bh)
+			 struct buffer_head *bh,
+			 struct ext4_xattr_inode_array **ea_inode_array,
+			 int extra_credits)
 {
 	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 	u32 hash, ref;
@@ -807,6 +1081,14 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
 		get_bh(bh);
 		unlock_buffer(bh);
+
+		if (ext4_has_feature_ea_inode(inode->i_sb))
+			ext4_xattr_inode_dec_ref_all(handle, inode, bh,
+						     BFIRST(bh),
+						     true /* block_csum */,
+						     ea_inode_array,
+						     extra_credits,
+						     true /* skip_quota */);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
 				 EXT4_FREE_BLOCKS_METADATA |
 				 EXT4_FREE_BLOCKS_FORGET);
@@ -947,7 +1229,7 @@ static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
  * Create an inode to store the value of a large EA.
  */
 static struct inode *ext4_xattr_inode_create(handle_t *handle,
-					     struct inode *inode)
+					     struct inode *inode, u32 hash)
 {
 	struct inode *ea_inode = NULL;
 	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
@@ -965,67 +1247,118 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 		ea_inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(ea_inode);
 		ext4_xattr_inode_set_class(ea_inode);
-		ea_inode->i_generation = inode->i_generation;
-		EXT4_I(ea_inode)->i_flags |= EXT4_EA_INODE_FL;
-
-		/*
-		 * A back-pointer from EA inode to parent inode will be useful
-		 * for e2fsck.
-		 */
-		EXT4_XATTR_INODE_SET_PARENT(ea_inode, inode->i_ino);
 		unlock_new_inode(ea_inode);
 		err = ext4_inode_attach_jinode(ea_inode);
+		if (!err)
+			err = ext4_xattr_inode_init(handle, ea_inode, hash);
 		if (err) {
 			iput(ea_inode);
 			return ERR_PTR(err);
 		}
+
+		/*
+		 * Xattr inodes are shared therefore quota charging is performed
+		 * at a higher level.
+		 */
+		dquot_free_inode(ea_inode);
+		dquot_drop(ea_inode);
+		inode_lock(ea_inode);
+		ea_inode->i_flags |= S_NOQUOTA;
+		inode_unlock(ea_inode);
 	}
 
 	return ea_inode;
 }
 
-/*
- * Unlink the inode storing the value of the EA.
- */
-int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino)
+static struct inode *
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+			    size_t value_len, u32 hash)
 {
-	struct inode *ea_inode = NULL;
+	struct inode *ea_inode;
+	struct mb_cache_entry *ce;
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+	void *ea_data = NULL;
 	int err;
 
-	err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-	if (err)
-		return err;
+	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
+	while (ce) {
+		ea_inode = ext4_iget(inode->i_sb, ce->e_value);
+		if (IS_ERR(ea_inode)) {
+			ea_inode = NULL;
+			goto next;
+		}
 
-	clear_nlink(ea_inode);
-	iput(ea_inode);
+		if (is_bad_inode(ea_inode) ||
+		    !(EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) ||
+		    i_size_read(ea_inode) != value_len)
+			goto next;
 
-	return 0;
+		if (!ea_data)
+			ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
+
+		if (!ea_data) {
+			iput(ea_inode);
+			return NULL;
+		}
+
+		err = ext4_xattr_inode_read(ea_inode, ea_data, value_len);
+		if (unlikely(err))
+			goto next;
+
+		if (!memcmp(value, ea_data, value_len)) {
+			mb_cache_entry_touch(ea_inode_cache, ce);
+			mb_cache_entry_put(ea_inode_cache, ce);
+			kvfree(ea_data);
+			return ea_inode;
+		}
+	next:
+		iput(ea_inode);
+		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
+	}
+	kvfree(ea_data);
+	return NULL;
 }
 
 /*
  * Add value of the EA in an inode.
  */
-static int ext4_xattr_inode_set(handle_t *handle, struct inode *inode,
-				unsigned long *ea_ino, const void *value,
-				size_t value_len)
+static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
+					  const void *value, size_t value_len,
+					  struct inode **ret_inode)
 {
+	u32 hash = ext4_xattr_inode_hash(value, value_len);
 	struct inode *ea_inode;
 	int err;
 
+	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
+	if (ea_inode) {
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			iput(ea_inode);
+			return err;
+		}
+
+		*ret_inode = ea_inode;
+		return 0;
+	}
+
 	/* Create an inode for the EA value */
-	ea_inode = ext4_xattr_inode_create(handle, inode);
+	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
 	if (IS_ERR(ea_inode))
 		return PTR_ERR(ea_inode);
 
 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
-	if (err)
-		clear_nlink(ea_inode);
-	else
-		*ea_ino = ea_inode->i_ino;
+	if (err) {
+		ext4_xattr_inode_dec_ref(handle, ea_inode);
+		iput(ea_inode);
+		return err;
+	}
 
-	iput(ea_inode);
+	mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
+			      ea_inode->i_ino, true /* reusable */);
 
-	return err;
+	*ret_inode = ea_inode;
+	return 0;
 }
 
 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
@@ -1033,11 +1366,37 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 				handle_t *handle, struct inode *inode)
 {
 	struct ext4_xattr_entry *last;
+	struct ext4_xattr_entry *here = s->here;
 	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 	int in_inode = i->in_inode;
-	int rc;
+	struct inode *old_ea_inode = NULL;
+	struct inode *new_ea_inode = NULL;
+	int ret;
 
-	/* Compute min_offs and last. */
+	/*
+	 * Optimization for the simple case when old and new values have the
+	 * same padded sizes. Not applicable if the existing value is stored in
+	 * an external inode.
+	 */
+	if (i->value && !s->not_found && !here->e_value_inum &&
+	    EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) ==
+	    EXT4_XATTR_SIZE(i->value_len)) {
+		size_t offs = le16_to_cpu(here->e_value_offs);
+		void *val = s->base + offs;
+		size_t size = EXT4_XATTR_SIZE(i->value_len);
+
+		here->e_value_size = cpu_to_le32(i->value_len);
+		if (i->value == EXT4_ZERO_XATTR_VALUE) {
+			memset(val, 0, size);
+		} else {
+			memcpy(val, i->value, i->value_len);
+			/* Clear padding bytes. */
+			memset(val + i->value_len, 0, size - i->value_len);
+		}
+		return 0;
+	}
+
+	/* Find out min_offs and last to calculate the free space. */
 	last = s->first;
 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 		if (!last->e_value_inum && last->e_value_size) {
@@ -1048,120 +1407,149 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 	}
 	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 	if (!s->not_found) {
-		if (!in_inode &&
-		    !s->here->e_value_inum && s->here->e_value_size) {
-			size_t size = le32_to_cpu(s->here->e_value_size);
+		if (!here->e_value_inum && here->e_value_size) {
+			size_t size = le32_to_cpu(here->e_value_size);
 			free += EXT4_XATTR_SIZE(size);
 		}
 		free += EXT4_XATTR_LEN(name_len);
 	}
 	if (i->value) {
-		size_t value_len = EXT4_XATTR_SIZE(i->value_len);
+		size_t value_len = in_inode ? 0 : EXT4_XATTR_SIZE(i->value_len);
 
-		if (in_inode)
-			value_len = 0;
+		if (free < EXT4_XATTR_LEN(name_len) + value_len) {
+			ret = -ENOSPC;
+			goto out;
+		}
+	}
 
-		if (free < EXT4_XATTR_LEN(name_len) + value_len)
-			return -ENOSPC;
+	/*
+	 * Getting access to old and new ea inodes is subject to failures.
+	 * Finish that work before doing any modifications to the xattr data.
+	 */
+	if (!s->not_found && here->e_value_inum) {
+		ret = ext4_xattr_inode_iget(inode,
+		 			    le32_to_cpu(here->e_value_inum),
+		 			    &old_ea_inode);
+		if (ret) {
+			old_ea_inode = NULL;
+			goto out;
+		}
 	}
+	if (i->value && in_inode) {
+		WARN_ON_ONCE(!i->value_len);
 
-	if (i->value && s->not_found) {
-		/* Insert the new name. */
-		size_t size = EXT4_XATTR_LEN(name_len);
-		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
-		memmove((void *)s->here + size, s->here, rest);
-		memset(s->here, 0, size);
-		s->here->e_name_index = i->name_index;
-		s->here->e_name_len = name_len;
-		memcpy(s->here->e_name, i->name, name_len);
-	} else {
-		if (!s->here->e_value_inum && s->here->e_value_size &&
-		    s->here->e_value_offs > 0) {
-			void *first_val = s->base + min_offs;
-			size_t offs = le16_to_cpu(s->here->e_value_offs);
-			void *val = s->base + offs;
-			size_t size = EXT4_XATTR_SIZE(
-				le32_to_cpu(s->here->e_value_size));
-
-			if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
-				/* The old and the new value have the same
-				   size. Just replace. */
-				s->here->e_value_size =
-					cpu_to_le32(i->value_len);
-				if (i->value == EXT4_ZERO_XATTR_VALUE) {
-					memset(val, 0, size);
-				} else {
-					/* Clear pad bytes first. */
-					memset(val + size - EXT4_XATTR_PAD, 0,
-					       EXT4_XATTR_PAD);
-					memcpy(val, i->value, i->value_len);
-				}
-				return 0;
-			}
+		ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
+		if (ret)
+			goto out;
 
-			/* Remove the old value. */
-			memmove(first_val + size, first_val, val - first_val);
-			memset(first_val, 0, size);
-			s->here->e_value_size = 0;
-			s->here->e_value_offs = 0;
-			min_offs += size;
-
-			/* Adjust all value offsets. */
-			last = s->first;
-			while (!IS_LAST_ENTRY(last)) {
-				size_t o = le16_to_cpu(last->e_value_offs);
-				if (!last->e_value_inum &&
-				    last->e_value_size && o < offs)
-					last->e_value_offs =
-						cpu_to_le16(o + size);
-				last = EXT4_XATTR_NEXT(last);
-			}
+		ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
+						     i->value_len,
+						     &new_ea_inode);
+		if (ret) {
+			new_ea_inode = NULL;
+			ext4_xattr_inode_free_quota(inode, i->value_len);
+			goto out;
 		}
-		if (s->here->e_value_inum) {
-			ext4_xattr_inode_unlink(inode,
-					    le32_to_cpu(s->here->e_value_inum));
-			s->here->e_value_inum = 0;
+	}
+
+	if (old_ea_inode) {
+		/* We are ready to release ref count on the old_ea_inode. */
+		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
+		if (ret) {
+			/* Release newly required ref count on new_ea_inode. */
+			if (new_ea_inode) {
+				int err;
+
+				err = ext4_xattr_inode_dec_ref(handle,
+							       new_ea_inode);
+				if (err)
+					ext4_warning_inode(new_ea_inode,
+						  "dec ref new_ea_inode err=%d",
+						  err);
+				ext4_xattr_inode_free_quota(inode,
+							    i->value_len);
+			}
+			goto out;
 		}
-		if (!i->value) {
-			/* Remove the old name. */
-			size_t size = EXT4_XATTR_LEN(name_len);
-			last = ENTRY((void *)last - size);
-			memmove(s->here, (void *)s->here + size,
-				(void *)last - (void *)s->here + sizeof(__u32));
-			memset(last, 0, size);
+
+		ext4_xattr_inode_free_quota(inode,
+					    le32_to_cpu(here->e_value_size));
+	}
+
+	/* No failures allowed past this point. */
+
+	if (!s->not_found && here->e_value_offs) {
+		/* Remove the old value. */
+		void *first_val = s->base + min_offs;
+		size_t offs = le16_to_cpu(here->e_value_offs);
+		void *val = s->base + offs;
+		size_t size = EXT4_XATTR_SIZE(
+			le32_to_cpu(here->e_value_size));
+
+		memmove(first_val + size, first_val, val - first_val);
+		memset(first_val, 0, size);
+		min_offs += size;
+
+		/* Adjust all value offsets. */
+		last = s->first;
+		while (!IS_LAST_ENTRY(last)) {
+			size_t o = le16_to_cpu(last->e_value_offs);
+			if (!last->e_value_inum &&
+			    last->e_value_size && o < offs)
+				last->e_value_offs =
+					cpu_to_le16(o + size);
+			last = EXT4_XATTR_NEXT(last);
 		}
 	}
 
+	if (!s->not_found && !i->value) {
+		/* Remove old name. */
+		size_t size = EXT4_XATTR_LEN(name_len);
+		last = ENTRY((void *)last - size);
+		memmove(here, (void *)here + size,
+			(void *)last - (void *)here + sizeof(__u32));
+		memset(last, 0, size);
+	} else if (s->not_found && i->value) {
+		/* Insert new name. */
+		size_t size = EXT4_XATTR_LEN(name_len);
+		size_t rest = (void *)last - (void *)here + sizeof(__u32);
+		memmove((void *)here + size, here, rest);
+		memset(here, 0, size);
+		here->e_name_index = i->name_index;
+		here->e_name_len = name_len;
+		memcpy(here->e_name, i->name, name_len);
+	} else {
+		WARN_ON_ONCE(s->not_found || !i->value);
+		/* This is an update, reset value info. */
+		here->e_value_inum = 0;
+		here->e_value_offs = 0;
+		here->e_value_size = 0;
+	}
+
 	if (i->value) {
-		/* Insert the new value. */
+		/* Insert new value. */
 		if (in_inode) {
-			unsigned long ea_ino =
-				le32_to_cpu(s->here->e_value_inum);
-			rc = ext4_xattr_inode_set(handle, inode, &ea_ino,
-						  i->value, i->value_len);
-			if (rc)
-				goto out;
-			s->here->e_value_inum = cpu_to_le32(ea_ino);
-			s->here->e_value_offs = 0;
+			here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
 		} else if (i->value_len) {
 			size_t size = EXT4_XATTR_SIZE(i->value_len);
 			void *val = s->base + min_offs - size;
-			s->here->e_value_offs = cpu_to_le16(min_offs - size);
-			s->here->e_value_inum = 0;
+			here->e_value_offs = cpu_to_le16(min_offs - size);
 			if (i->value == EXT4_ZERO_XATTR_VALUE) {
 				memset(val, 0, size);
 			} else {
-				/* Clear the pad bytes first. */
-				memset(val + size - EXT4_XATTR_PAD, 0,
-				       EXT4_XATTR_PAD);
 				memcpy(val, i->value, i->value_len);
+				/* Clear padding bytes. */
+				memset(val + i->value_len, 0,
+				       size - i->value_len);
 			}
 		}
-		s->here->e_value_size = cpu_to_le32(i->value_len);
+		here->e_value_size = cpu_to_le32(i->value_len);
 	}
-
+	ret = 0;
 out:
-	return rc;
+	iput(old_ea_inode);
+	iput(new_ea_inode);
+	return ret;
 }
 
 struct ext4_xattr_block_find {
@@ -1223,6 +1611,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 	struct mb_cache_entry *ce = NULL;
 	int error = 0;
 	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
+	struct inode *ea_inode = NULL;
+	size_t old_ea_inode_size = 0;
 
 #define header(x) ((struct ext4_xattr_header *)(x))
 
@@ -1277,6 +1667,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			header(s->base)->h_refcount = cpu_to_le32(1);
 			s->here = ENTRY(s->base + offset);
 			s->end = s->base + bs->bh->b_size;
+
+			/*
+			 * If existing entry points to an xattr inode, we need
+			 * to prevent ext4_xattr_set_entry() from decrementing
+			 * ref count on it because the reference belongs to the
+			 * original block. In this case, make the entry look
+			 * like it has an empty value.
+			 */
+			if (!s->not_found && s->here->e_value_inum) {
+				/*
+				 * Defer quota free call for previous inode
+				 * until success is guaranteed.
+				 */
+				old_ea_inode_size = le32_to_cpu(
+							s->here->e_value_size);
+				s->here->e_value_inum = 0;
+				s->here->e_value_size = 0;
+			}
 		}
 	} else {
 		/* Allocate a buffer where we construct the new block. */
@@ -1298,6 +1706,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 		goto bad_block;
 	if (error)
 		goto cleanup;
+
+	if (i->value && s->here->e_value_inum) {
+		unsigned int ea_ino;
+
+		/*
+		 * A ref count on ea_inode has been taken as part of the call to
+		 * ext4_xattr_set_entry() above. We would like to drop this
+		 * extra ref but we have to wait until the xattr block is
+		 * initialized and has its own ref count on the ea_inode.
+		 */
+		ea_ino = le32_to_cpu(s->here->e_value_inum);
+		error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+		if (error) {
+			ea_inode = NULL;
+			goto cleanup;
+		}
+	}
+
 	if (!IS_LAST_ENTRY(s->first))
 		ext4_xattr_rehash(header(s->base), s->here);
 
@@ -1408,6 +1834,22 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 						 EXT4_FREE_BLOCKS_METADATA);
 				goto cleanup;
 			}
+			error = ext4_xattr_inode_inc_ref_all(handle, inode,
+						      ENTRY(header(s->base)+1));
+			if (error)
+				goto getblk_failed;
+			if (ea_inode) {
+				/* Drop the extra ref on ea_inode. */
+				error = ext4_xattr_inode_dec_ref(handle,
+								 ea_inode);
+				if (error)
+					ext4_warning_inode(ea_inode,
+							   "dec ref error=%d",
+							   error);
+				iput(ea_inode);
+				ea_inode = NULL;
+			}
+
 			lock_buffer(new_bh);
 			error = ext4_journal_get_create_access(handle, new_bh);
 			if (error) {
@@ -1427,15 +1869,36 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 		}
 	}
 
+	if (old_ea_inode_size)
+		ext4_xattr_inode_free_quota(inode, old_ea_inode_size);
+
 	/* Update the inode. */
 	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 
 	/* Drop the previous xattr block. */
-	if (bs->bh && bs->bh != new_bh)
-		ext4_xattr_release_block(handle, inode, bs->bh);
+	if (bs->bh && bs->bh != new_bh) {
+		struct ext4_xattr_inode_array *ea_inode_array = NULL;
+		ext4_xattr_release_block(handle, inode, bs->bh,
+					 &ea_inode_array,
+					 0 /* extra_credits */);
+		ext4_xattr_inode_array_free(ea_inode_array);
+	}
 	error = 0;
 
 cleanup:
+	if (ea_inode) {
+		int error2;
+		error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (error2)
+			ext4_warning_inode(ea_inode, "dec ref error=%d",
+					   error2);
+
+		/* If there was an error, revert the quota charge. */
+		if (error)
+			ext4_xattr_inode_free_quota(inode,
+						    i_size_read(ea_inode));
+		iput(ea_inode);
+	}
 	if (ce)
 		mb_cache_entry_put(ext4_mb_cache, ce);
 	brelse(new_bh);
@@ -1546,6 +2009,117 @@ static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 	return 0;
 }
 
+struct ext4_xattr_ea_info {
+	__le64 ref_count;	/* number of xattr entry references */
+	__le32 hash;		/* crc32c hash of xattr data */
+	__le32 reserved;	/* reserved, must be 0 */
+};
+
+static int ext4_xattr_inode_init(handle_t *handle, struct inode *ea_inode,
+				 u32 hash)
+{
+	struct ext4_xattr_ea_info ea_info = {
+		.ref_count = cpu_to_le64(1),
+		.hash = cpu_to_le32(hash),
+		.reserved = 0,
+	};
+	struct ext4_xattr_info i = {
+                .name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_EA_INFO,
+		.value = &ea_info,
+		.value_len = sizeof(ea_info),
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int err;
+
+	err = ext4_get_inode_loc(ea_inode, &is.iloc);
+	if (err)
+		return err;
+
+	err = ext4_xattr_ibody_find(ea_inode, &i, &is);
+	if (err)
+		return err;
+
+	return ext4_xattr_ibody_set(handle, ea_inode, &i, &is);
+}
+
+static int ext4_xattr_update_ea_info(struct inode *ea_inode, int ref_change,
+				     u64 *ref_return, u32 *hash)
+{
+	struct ext4_xattr_ea_info ea_info;
+	struct ext4_xattr_info i = {
+                .name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_EA_INFO,
+		.value = &ea_info,
+		.value_len = sizeof(ea_info),
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int err;
+
+	err = ext4_get_inode_loc(ea_inode, &is.iloc);
+	if (err)
+		return err;
+
+	err = ext4_xattr_ibody_find(ea_inode, &i, &is);
+	if (err)
+		return err;
+
+	if (WARN_ON(is.s.not_found) ||
+	    WARN_ON(le32_to_cpu(is.s.here->e_value_size) != sizeof(ea_info)))
+		return -EFSCORRUPTED;
+
+	memcpy(&ea_info,
+	       ((void *)is.s.base) + le16_to_cpu(is.s.here->e_value_offs),
+	       sizeof(ea_info));
+
+	if (hash)
+		*hash = le32_to_cpu(ea_info.hash);
+
+	*ref_return = le64_to_cpu(ea_info.ref_count) + ref_change;
+	ea_info.ref_count = cpu_to_le64(*ref_return);
+
+	return ext4_xattr_set_entry(&i, &is.s, NULL, ea_inode);
+}
+
+static int ext4_xattr_read_ea_hash(struct inode *ea_inode, u32 *hash)
+{
+	struct ext4_xattr_info i = {
+                .name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_EA_INFO,
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_ea_info *ea_info;
+	void *ptr;
+	int err;
+
+	err = ext4_get_inode_loc(ea_inode, &is.iloc);
+	if (err)
+		return err;
+
+	err = ext4_xattr_ibody_find(ea_inode, &i, &is);
+	if (err)
+		return err;
+
+	if (WARN_ON(is.s.not_found) ||
+	    WARN_ON(le32_to_cpu(is.s.here->e_value_size) != sizeof(*ea_info)))
+		return -EFSCORRUPTED;
+
+	ptr = ((void *)is.s.base) + le16_to_cpu(is.s.here->e_value_offs);
+	ea_info = (struct ext4_xattr_ea_info *)ptr;
+
+	if (WARN_ON(ea_info->reserved != 0))
+		return -EFSCORRUPTED;
+
+	*hash = le32_to_cpu(ea_info->hash);
+	return 0;
+}
+
 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
 				 struct ext4_xattr_info *i)
 {
@@ -1560,6 +2134,22 @@ static int ext4_xattr_value_same(struct ext4_xattr_search *s,
 	return !memcmp(value, i->value, i->value_len);
 }
 
+struct buffer_head *ext4_xattr_get_block(struct inode *inode)
+{
+	struct buffer_head *bh;
+	int error;
+
+	if (!EXT4_I(inode)->i_file_acl)
+		return NULL;
+	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+	if (!bh)
+		return ERR_PTR(-EIO);
+	error = ext4_xattr_check_block(inode, bh);
+	if (error)
+		return ERR_PTR(error);
+	return bh;
+}
+
 /*
  * ext4_xattr_set_handle()
  *
@@ -1602,9 +2192,18 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 
 	/* Check journal credits under write lock. */
 	if (ext4_handle_valid(handle)) {
+		struct buffer_head *bh;
 		int credits;
 
-		credits = ext4_xattr_set_credits(inode, value_len);
+		bh = ext4_xattr_get_block(inode);
+		if (IS_ERR(bh)) {
+			error = PTR_ERR(bh);
+			goto cleanup;
+		}
+
+		credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+		brelse(bh);
+
 		if (!ext4_handle_has_enough_credits(handle, credits)) {
 			error = -ENOSPC;
 			goto cleanup;
@@ -1640,6 +2239,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 		if (flags & XATTR_CREATE)
 			goto cleanup;
 	}
+
 	if (!value) {
 		if (!is.s.not_found)
 			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
@@ -1708,34 +2308,29 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 	return error;
 }
 
-int ext4_xattr_set_credits(struct inode *inode, size_t value_len)
+int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
 {
-	struct super_block *sb = inode->i_sb;
-	int credits;
-
-	if (!EXT4_SB(sb)->s_journal)
-		return 0;
-
-	credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+	struct buffer_head *bh;
+	int err;
 
-	/*
-	 * In case of inline data, we may push out the data to a block,
-	 * so we need to reserve credits for this eventuality
-	 */
-	if (ext4_has_inline_data(inode))
-	        credits += ext4_writepage_trans_blocks(inode) + 1;
+	*credits = 0;
 
-	if (ext4_has_feature_ea_inode(sb)) {
-		int nrblocks = (value_len + sb->s_blocksize - 1) >>
-					sb->s_blocksize_bits;
+	if (!EXT4_SB(inode->i_sb)->s_journal)
+		return 0;
 
-		/* For new inode */
-		credits += EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + 3;
+	down_read(&EXT4_I(inode)->xattr_sem);
 
-		/* For data blocks of EA inode */
-		credits += ext4_meta_trans_blocks(inode, nrblocks, 0);
+	bh = ext4_xattr_get_block(inode);
+	if (IS_ERR(bh)) {
+		err = PTR_ERR(bh);
+	} else {
+		*credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+		brelse(bh);
+		err = 0;
 	}
-	return credits;
+
+	up_read(&EXT4_I(inode)->xattr_sem);
+	return err;
 }
 
 /*
@@ -1760,7 +2355,10 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 		return error;
 
 retry:
-	credits = ext4_xattr_set_credits(inode, value_len);
+	error = ext4_xattr_set_credits(inode, value_len, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle)) {
 		error = PTR_ERR(handle);
@@ -2066,10 +2664,10 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 	return error;
 }
 
-
 #define EIA_INCR 16 /* must be 2^n */
 #define EIA_MASK (EIA_INCR - 1)
-/* Add the large xattr @inode into @ea_inode_array for later deletion.
+
+/* Add the large xattr @inode into @ea_inode_array for deferred iput().
  * If @ea_inode_array is new or full it will be grown and the old
  * contents copied over.
  */
@@ -2114,21 +2712,19 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
  * ext4_xattr_delete_inode()
  *
  * Free extended attribute resources associated with this inode. Traverse
- * all entries and unlink any xattr inodes associated with this inode. This
- * is called immediately before an inode is freed. We have exclusive
- * access to the inode. If an orphan inode is deleted it will also delete any
- * xattr block and all xattr inodes. They are checked by ext4_xattr_inode_iget()
- * to ensure they belong to the parent inode and were not deleted already.
+ * all entries and decrement reference on any xattr inodes associated with this
+ * inode. This is called immediately before an inode is freed. We have exclusive
+ * access to the inode. If an orphan inode is deleted it will also release its
+ * references on xattr block and xattr inodes.
  */
-int
-ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-			struct ext4_xattr_inode_array **ea_inode_array,
-			int extra_credits)
+int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+			    struct ext4_xattr_inode_array **ea_inode_array,
+			    int extra_credits)
 {
 	struct buffer_head *bh = NULL;
 	struct ext4_xattr_ibody_header *header;
-	struct ext4_inode *raw_inode;
 	struct ext4_iloc iloc = { .bh = NULL };
+	struct ext4_xattr_entry *entry;
 	int error;
 
 	error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
@@ -2140,66 +2736,71 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 		goto cleanup;
 	}
 
-	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
-		goto delete_external_ea;
-
-	error = ext4_get_inode_loc(inode, &iloc);
-	if (error)
-		goto cleanup;
+	if (ext4_has_feature_ea_inode(inode->i_sb) &&
+	    ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 
-	error = ext4_journal_get_write_access(handle, iloc.bh);
-	if (error)
-		goto cleanup;
+		error = ext4_get_inode_loc(inode, &iloc);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
+			goto cleanup;
+		}
 
-	raw_inode = ext4_raw_inode(&iloc);
-	header = IHDR(inode, raw_inode);
-	ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),
-				    false /* block_csum */, ea_inode_array,
-				    extra_credits);
+		error = ext4_journal_get_write_access(handle, iloc.bh);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "write access (error %d)",
+					 error);
+			goto cleanup;
+		}
 
-delete_external_ea:
-	if (!EXT4_I(inode)->i_file_acl) {
-		error = 0;
-		goto cleanup;
-	}
-	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
-	if (!bh) {
-		EXT4_ERROR_INODE(inode, "block %llu read error",
-				 EXT4_I(inode)->i_file_acl);
-		error = -EIO;
-		goto cleanup;
-	}
-	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
-	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
-		EXT4_ERROR_INODE(inode, "bad block %llu",
-				 EXT4_I(inode)->i_file_acl);
-		error = -EFSCORRUPTED;
-		goto cleanup;
+		header = IHDR(inode, ext4_raw_inode(&iloc));
+		if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+			ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
+						     IFIRST(header),
+						     false /* block_csum */,
+						     ea_inode_array,
+						     extra_credits,
+						     false /* skip_quota */);
 	}
 
-	if (ext4_has_feature_ea_inode(inode->i_sb)) {
-		error = ext4_journal_get_write_access(handle, bh);
-		if (error) {
-			EXT4_ERROR_INODE(inode, "write access %llu",
+	if (EXT4_I(inode)->i_file_acl) {
+		bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+		if (!bh) {
+			EXT4_ERROR_INODE(inode, "block %llu read error",
 					 EXT4_I(inode)->i_file_acl);
+			error = -EIO;
+			goto cleanup;
+		}
+		error = ext4_xattr_check_block(inode, bh);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
+					 EXT4_I(inode)->i_file_acl, error);
 			goto cleanup;
 		}
-		ext4_xattr_inode_remove_all(handle, inode, bh,
-					    BFIRST(bh),
-					    true /* block_csum */,
-					    ea_inode_array,
-					    extra_credits);
-	}
 
-	ext4_xattr_release_block(handle, inode, bh);
-	/* Update i_file_acl within the same transaction that releases block. */
-	EXT4_I(inode)->i_file_acl = 0;
-	error = ext4_mark_inode_dirty(handle, inode);
-	if (error) {
-		EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
-				 error);
-		goto cleanup;
+		if (ext4_has_feature_ea_inode(inode->i_sb)) {
+			for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+			     entry = EXT4_XATTR_NEXT(entry))
+				if (entry->e_value_inum)
+					ext4_xattr_inode_free_quota(inode,
+					      le32_to_cpu(entry->e_value_size));
+
+		}
+
+		ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
+					 extra_credits);
+		/*
+		 * Update i_file_acl value in the same transaction that releases
+		 * block.
+		 */
+		EXT4_I(inode)->i_file_acl = 0;
+		error = ext4_mark_inode_dirty(handle, inode);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+					 error);
+			goto cleanup;
+		}
 	}
+	error = 0;
 cleanup:
 	brelse(iloc.bh);
 	brelse(bh);
@@ -2208,17 +2809,13 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 
 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
 {
-	struct inode	*ea_inode;
-	int		idx = 0;
+	int idx;
 
 	if (ea_inode_array == NULL)
 		return;
 
-	for (; idx < ea_inode_array->count; ++idx) {
-		ea_inode = ea_inode_array->inodes[idx];
-		clear_nlink(ea_inode);
-		iput(ea_inode);
-	}
+	for (idx = 0; idx < ea_inode_array->count; ++idx)
+		iput(ea_inode_array->inodes[idx]);
 	kfree(ea_inode_array);
 }
 
fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -70,19 +70,6 @@ struct ext4_xattr_entry {
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
 /*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
-/*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
 */
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 77a5b99d8f92..7dfdca822ccb 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#48 lore raw

PATCH v2 27/28 ext4: xattr inode deduplication

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |   22 +-
 fs/ext4/inode.c |    9 +-
 fs/ext4/super.c |   25 +-
 fs/ext4/xattr.c | 1075 +++++++++++++++++++++++++++++++++++++++++++------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 893 insertions(+), 269 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +14 -8
index d79d8d7bee88..7ceb1f81e4b8 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
@@ -2709,19 +2714,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
 				    ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-	return ext4_has_feature_gdt_csum(sb) ||
-	       EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
 	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
 		     !EXT4_SB(sb)->s_chksum_driver);
 
-	return (EXT4_SB(sb)->s_chksum_driver != NULL);
+	return ext4_has_feature_metadata_csum(sb) &&
+	       (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +8 -1
index 4d6936f0d8a4..6f5872197d6c 100644
@@ -4843,8 +4843,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/super.c +23 -2
index b02a23ec92ca..9fcd29e21dc7 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Load the checksum driver */
-	if (ext4_has_feature_metadata_csum(sb)) {
+	if (ext4_has_feature_metadata_csum(sb) ||
+	    ext4_has_feature_ea_inode(sb)) {
 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
 		if (IS_ERR(sbi->s_chksum_driver)) {
 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -4067,6 +4075,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4313,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +837 -238

1,360 lines not on this page · raw message

fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -70,19 +70,6 @@ struct ext4_xattr_entry {
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
 /*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
-/*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
 */
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 77a5b99d8f92..7dfdca822ccb 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#49 lore raw

Re: [PATCH v2 27/28] ext4: xattr inode deduplication

Quoted 243 lines · Tahsin Erdogan

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |   22 +-
 fs/ext4/inode.c |    9 +-
 fs/ext4/super.c |   25 +-
 fs/ext4/xattr.c | 1075 +++++++++++++++++++++++++++++++++++++++++++------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 893 insertions(+), 269 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +14 -8
index d79d8d7bee88..7ceb1f81e4b8 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
@@ -2709,19 +2714,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
 				    ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-	return ext4_has_feature_gdt_csum(sb) ||
-	       EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
 	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
 		     !EXT4_SB(sb)->s_chksum_driver);
 
-	return (EXT4_SB(sb)->s_chksum_driver != NULL);
+	return ext4_has_feature_metadata_csum(sb) &&
+	       (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +8 -1
index 4d6936f0d8a4..6f5872197d6c 100644
@@ -4843,8 +4843,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/super.c +23 -2
index b02a23ec92ca..9fcd29e21dc7 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Load the checksum driver */
-	if (ext4_has_feature_metadata_csum(sb)) {
+	if (ext4_has_feature_metadata_csum(sb) ||
+	    ext4_has_feature_ea_inode(sb)) {
 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
 		if (IS_ERR(sbi->s_chksum_driver)) {
 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -4067,6 +4075,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4313,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +11 -8
index 6acce1f689ab..4c394411bf6f 100644
@@ -79,6 +79,7 @@ ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *,
 			    struct mb_cache_entry **);
 static void ext4_xattr_rehash(struct ext4_xattr_header *,
 			      struct ext4_xattr_entry *);
+static int ext4_xattr_read_ea_hash(struct inode *ea_inode, u32 *hash);
 
 static const struct xattr_handler * const ext4_xattr_handler_map[] = {
 	[EXT4_XATTR_INDEX_USER]		     = &ext4_xattr_user_handler,
@@ -105,13 +106,23 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 	NULL
 };
 
+#define EXT4_XATTR_SYSTEM_EA_INFO  "eai"
+
 #define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
 				inode->i_sb->s_fs_info)->s_mb_cache)
 
+#define EA_INODE_CACHE(inode)	(((struct ext4_sb_info *) \
+				inode->i_sb->s_fs_info)->s_ea_inode_cache)
+
 static int
 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 			struct inode *inode);
 
+static int ext4_xattr_inode_init(handle_t *handle, struct inode *ea_inode,
+				 u32 hash);
+static int ext4_xattr_update_ea_info(struct inode *ea_inode, int ref_change,
+				     u64 *ref_return, u32 *hash);
+
 #ifdef CONFIG_LOCKDEP
 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 {
@@ -329,14 +340,6 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 		goto error;
 	}
 
-	if (EXT4_XATTR_INODE_GET_PARENT(inode) != parent->i_ino ||
-	    inode->i_generation != parent->i_generation) {
-		ext4_error(parent->i_sb, "Backpointer from EA inode %lu "
-			   "to parent is invalid.", ea_ino);
-		err = -EINVAL;
-		goto error;
-	}
-
 	if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
 		ext4_error(parent->i_sb, "EA inode %lu does not have "
 			   "EXT4_EA_INODE_FL flag set.\n", ea_ino);

fs/ext4/xattr.c static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino, · line 360

Quoted 7 lines
fs/ext4/xattr.c +4 -0
@@ -351,6 +354,12 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 	return err;
 }
 
+static u32
+ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
+{
+	return ext4_chksum(sbi, 0, buffer, size);

Hmm... normally we'd supply sbi->s_csum_seed as the second argument so that the metadata checksum value also has the fs uuid stamped into it. That way if we ever encounter a piece of metadata we can positively confirm that it belongs to this filesystem (vs. a piece of metadata that came from a previous ext4 that had been written to the disk) or discard it as being a ghost from an old iteration. For xattrs I think we were also baking in either the owning inode number (refcount == 1) or the block number (refcount > 1) so that there's some redundant parent pointer information encoded in the checksum too.

Even if you dismiss that, we usually follow the convention of initializing the crc32c calculation with (~0U), not (0U), to strengthen crc32c's ability to detect zeroes being injected at the start of the stream.

--D

Quoted 1,393 lines
fs/ext4/xattr.c +822 -230
+}
+
 /*
  * Read the value from the EA inode.
  */
@@ -358,17 +367,53 @@ static int
 ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
 		     size_t size)
 {
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
 	struct inode *ea_inode;
-	int ret;
+	u32 hash, calc_hash;
+	struct mb_cache_entry *ce;
+	int err;
 
-	ret = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-	if (ret)
-		return ret;
+	err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+	if (err) {
+		ea_inode = NULL;
+		goto out;
+	}
 
-	ret = ext4_xattr_inode_read(ea_inode, buffer, size);
-	iput(ea_inode);
+	if (i_size_read(ea_inode) != size) {
+		ext4_warning_inode(ea_inode,
+				   "ea_inode file size=%llu entry size=%zu",
+				   i_size_read(ea_inode), size);
+		err = -EFSCORRUPTED;
+		goto out;
+	}
 
-	return ret;
+	err = ext4_xattr_inode_read(ea_inode, buffer, size);
+	if (!err) {
+		if (ext4_xattr_read_ea_hash(ea_inode, &hash))
+			goto out;
+
+		/* Avoid hash calculation if already cached. */
+		ce = mb_cache_entry_get(ea_inode_cache, hash, ea_inode->i_ino);
+		if (ce) {
+			mb_cache_entry_put(ea_inode_cache, ce);
+			goto out;
+		}
+
+		calc_hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), buffer,
+						  size);
+		if (hash != calc_hash) {
+			ext4_warning_inode(ea_inode, "EA inode saved hash=%#x "
+					   "does not match calc_hash=%#x",
+					   hash, calc_hash);
+			goto out;
+		}
+
+		mb_cache_entry_create(ea_inode_cache, GFP_NOFS, hash,
+				      ea_inode->i_ino, true /* reusable */);
+	}
+out:
+	iput(ea_inode);
+	return err;
 }
 
 static int
@@ -657,6 +702,101 @@ static void ext4_xattr_update_super_block(handle_t *handle,
 	}
 }
 
+static inline size_t round_up_cluster(struct inode *inode, size_t length)
+{
+	struct super_block *sb = inode->i_sb;
+	size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
+				    inode->i_blkbits);
+	size_t mask = ~(cluster_size - 1);
+
+	return (length + cluster_size - 1) & mask;
+}
+
+static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
+{
+	int err;
+
+	err = dquot_alloc_inode(inode);
+	if (err)
+		return err;
+	err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
+	if (err)
+		dquot_free_inode(inode);
+	return err;
+}
+
+static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
+{
+	dquot_free_space_nodirty(inode, round_up_cluster(inode, len));
+	dquot_free_inode(inode);
+}
+
+static int __ext4_xattr_set_credits(struct super_block *sb,
+				    struct buffer_head *block_bh,
+				    size_t value_len)
+{
+	int credits;
+	int blocks;
+
+	/*
+	 * 1) Owner inode update
+	 * 2) Ref count update on old xattr block
+	 * 3) new xattr block
+	 * 4) block bitmap update for new xattr block
+	 * 5) group descriptor for new xattr block
+	 */
+	credits = 5;
+
+	/* We are done if ea_inode feature is not enabled. */
+	if (!ext4_has_feature_ea_inode(sb))
+		return credits;
+
+	/* New ea_inode, inode map, block bitmap, group descriptor. */
+	credits += 4;
+
+	/* Data blocks. */
+	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+
+	/* Indirection block. */
+	blocks += 1;
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Blocks themselves. */
+	credits += blocks;
+
+	/* Dereference ea_inode holding old xattr value.
+	 * Old ea_inode, inode map, block bitmap, group descriptor.
+	 */
+	credits += 4;
+
+	/* Data blocks for old ea_inode. */
+	blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+
+	/* Indirection block for old ea_inode. */
+	blocks += 1;
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Quota updates. */
+	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
+
+	/* We may need to clone the existing xattr block in which case we need
+	 * to increment ref counts for existing ea_inodes referenced by it.
+	 */
+	if (block_bh) {
+		struct ext4_xattr_entry *entry = BFIRST(block_bh);
+
+		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				/* Ref count update on ea_inode. */
+				credits += 1;
+	}
+	return credits;
+}
+
 int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 			      int credits, struct buffer_head *bh,
 			      bool dirty, bool block_csum)
@@ -706,12 +846,139 @@ int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
 	return 0;
 }
 
+static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
+				       int ref_change)
+{
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
+	struct ext4_iloc iloc;
+	s64 ref_return;
+	u32 hash;
+	int ret;
+
+	inode_lock(ea_inode);
+
+	ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
+	if (ret) {
+		iloc.bh = NULL;
+		goto out;
+	}
+
+	ret = ext4_xattr_update_ea_info(ea_inode, ref_change, &ref_return,
+					&hash);
+	if (ret)
+		goto out;
+
+	if (ref_change > 0) {
+		WARN_ONCE(ref_return <= 0, "EA inode %lu ref_return=%lld",
+			  ea_inode->i_ino, ref_return);
+
+		if (ref_return == 1) {
+			WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
+				  ea_inode->i_ino, ea_inode->i_nlink);
+
+			set_nlink(ea_inode, 1);
+			ext4_orphan_del(handle, ea_inode);
+
+			mb_cache_entry_create(ea_inode_cache, GFP_NOFS, hash,
+					      ea_inode->i_ino,
+					      true /* reusable */);
+		}
+	} else {
+		WARN_ONCE(ref_return < 0, "EA inode %lu ref_return=%lld",
+			  ea_inode->i_ino, ref_return);
+
+		if (ref_return == 0) {
+			WARN_ONCE(ea_inode->i_nlink != 1,
+				  "EA inode %lu i_nlink=%u",
+				  ea_inode->i_ino, ea_inode->i_nlink);
+
+			clear_nlink(ea_inode);
+			ext4_orphan_add(handle, ea_inode);
+
+			mb_cache_entry_delete(ea_inode_cache, hash,
+					      ea_inode->i_ino);
+		}
+	}
+
+	ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
+	iloc.bh = NULL;
+	if (ret)
+		ext4_warning_inode(ea_inode,
+				   "ext4_mark_iloc_dirty() failed ret=%d", ret);
+out:
+	brelse(iloc.bh);
+	inode_unlock(ea_inode);
+	return ret;
+}
+
+static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
+{
+	return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
+}
+
+static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
+{
+	return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
+}
+
+static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
+					struct ext4_xattr_entry *first)
+{
+	struct inode *ea_inode;
+	struct ext4_xattr_entry *entry;
+	struct ext4_xattr_entry *failed_entry;
+	unsigned int ea_ino;
+	int err, saved_err;
+
+	for (entry = first; !IS_LAST_ENTRY(entry);
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+		if (err)
+			goto cleanup;
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode, "inc ref error %d", err);
+			iput(ea_inode);
+			goto cleanup;
+		}
+		iput(ea_inode);
+	}
+	return 0;
+
+cleanup:
+	saved_err = err;
+	failed_entry = entry;
+
+	for (entry = first; entry != failed_entry;
+	     entry = EXT4_XATTR_NEXT(entry)) {
+		if (!entry->e_value_inum)
+			continue;
+		ea_ino = le32_to_cpu(entry->e_value_inum);
+		err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+		if (err) {
+			ext4_warning(parent->i_sb,
+				     "cleanup ea_ino %u iget error %d", ea_ino,
+				     err);
+			continue;
+		}
+		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (err)
+			ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
+					   err);
+		iput(ea_inode);
+	}
+	return saved_err;
+}
+
 static void
-ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
-			    struct buffer_head *bh,
-			    struct ext4_xattr_entry *first, bool block_csum,
-			    struct ext4_xattr_inode_array **ea_inode_array,
-			    int extra_credits)
+ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
+			     struct buffer_head *bh,
+			     struct ext4_xattr_entry *first, bool block_csum,
+			     struct ext4_xattr_inode_array **ea_inode_array,
+			     int extra_credits, bool skip_quota)
 {
 	struct inode *ea_inode;
 	struct ext4_xattr_entry *entry;
@@ -748,10 +1015,16 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
 			continue;
 		}
 
-		inode_lock(ea_inode);
-		clear_nlink(ea_inode);
-		ext4_orphan_add(handle, ea_inode);
-		inode_unlock(ea_inode);
+		err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (err) {
+			ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
+					   err);
+			continue;
+		}
+
+		if (!skip_quota)
+			ext4_xattr_inode_free_quota(parent,
+					      le32_to_cpu(entry->e_value_size));
 
 		/*
 		 * Forget about ea_inode within the same transaction that decrements the ref
@@ -784,7 +1057,9 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
  */
 static void
 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
-			 struct buffer_head *bh)
+			 struct buffer_head *bh,
+			 struct ext4_xattr_inode_array **ea_inode_array,
+			 int extra_credits)
 {
 	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
 	u32 hash, ref;
@@ -807,6 +1082,14 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
 		mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
 		get_bh(bh);
 		unlock_buffer(bh);
+
+		if (ext4_has_feature_ea_inode(inode->i_sb))
+			ext4_xattr_inode_dec_ref_all(handle, inode, bh,
+						     BFIRST(bh),
+						     true /* block_csum */,
+						     ea_inode_array,
+						     extra_credits,
+						     true /* skip_quota */);
 		ext4_free_blocks(handle, inode, bh, 0, 1,
 				 EXT4_FREE_BLOCKS_METADATA |
 				 EXT4_FREE_BLOCKS_FORGET);
@@ -947,7 +1230,7 @@ static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
  * Create an inode to store the value of a large EA.
  */
 static struct inode *ext4_xattr_inode_create(handle_t *handle,
-					     struct inode *inode)
+					     struct inode *inode, u32 hash)
 {
 	struct inode *ea_inode = NULL;
 	uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
@@ -965,67 +1248,119 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
 		ea_inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(ea_inode);
 		ext4_xattr_inode_set_class(ea_inode);
-		ea_inode->i_generation = inode->i_generation;
-		EXT4_I(ea_inode)->i_flags |= EXT4_EA_INODE_FL;
-
-		/*
-		 * A back-pointer from EA inode to parent inode will be useful
-		 * for e2fsck.
-		 */
-		EXT4_XATTR_INODE_SET_PARENT(ea_inode, inode->i_ino);
 		unlock_new_inode(ea_inode);
 		err = ext4_inode_attach_jinode(ea_inode);
+		if (!err)
+			err = ext4_xattr_inode_init(handle, ea_inode, hash);
 		if (err) {
 			iput(ea_inode);
 			return ERR_PTR(err);
 		}
+
+		/*
+		 * Xattr inodes are shared therefore quota charging is performed
+		 * at a higher level.
+		 */
+		dquot_free_inode(ea_inode);
+		dquot_drop(ea_inode);
+		inode_lock(ea_inode);
+		ea_inode->i_flags |= S_NOQUOTA;
+		inode_unlock(ea_inode);
 	}
 
 	return ea_inode;
 }
 
-/*
- * Unlink the inode storing the value of the EA.
- */
-int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino)
+static struct inode *
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+			    size_t value_len, u32 hash)
 {
-	struct inode *ea_inode = NULL;
+	struct inode *ea_inode;
+	struct mb_cache_entry *ce;
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+	void *ea_data = NULL;
 	int err;
 
-	err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-	if (err)
-		return err;
+	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
+	while (ce) {
+		ea_inode = ext4_iget(inode->i_sb, ce->e_value);
+		if (IS_ERR(ea_inode)) {
+			ea_inode = NULL;
+			goto next;
+		}
 
-	clear_nlink(ea_inode);
-	iput(ea_inode);
+		if (is_bad_inode(ea_inode) ||
+		    !(EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) ||
+		    i_size_read(ea_inode) != value_len)
+			goto next;
 
-	return 0;
+		if (!ea_data)
+			ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
+
+		if (!ea_data) {
+			iput(ea_inode);
+			return NULL;
+		}
+
+		err = ext4_xattr_inode_read(ea_inode, ea_data, value_len);
+		if (unlikely(err))
+			goto next;
+
+		if (!memcmp(value, ea_data, value_len)) {
+			mb_cache_entry_touch(ea_inode_cache, ce);
+			mb_cache_entry_put(ea_inode_cache, ce);
+			kvfree(ea_data);
+			return ea_inode;
+		}
+	next:
+		iput(ea_inode);
+		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
+	}
+	kvfree(ea_data);
+	return NULL;
 }
 
 /*
  * Add value of the EA in an inode.
  */
-static int ext4_xattr_inode_set(handle_t *handle, struct inode *inode,
-				unsigned long *ea_ino, const void *value,
-				size_t value_len)
+static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
+					  const void *value, size_t value_len,
+					  struct inode **ret_inode)
 {
 	struct inode *ea_inode;
+	u32 hash;
 	int err;
 
+	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
+	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
+	if (ea_inode) {
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			iput(ea_inode);
+			return err;
+		}
+
+		*ret_inode = ea_inode;
+		return 0;
+	}
+
 	/* Create an inode for the EA value */
-	ea_inode = ext4_xattr_inode_create(handle, inode);
+	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
 	if (IS_ERR(ea_inode))
 		return PTR_ERR(ea_inode);
 
 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
-	if (err)
-		clear_nlink(ea_inode);
-	else
-		*ea_ino = ea_inode->i_ino;
+	if (err) {
+		ext4_xattr_inode_dec_ref(handle, ea_inode);
+		iput(ea_inode);
+		return err;
+	}
 
-	iput(ea_inode);
+	mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
+			      ea_inode->i_ino, true /* reusable */);
 
-	return err;
+	*ret_inode = ea_inode;
+	return 0;
 }
 
 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
@@ -1033,11 +1368,37 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 				handle_t *handle, struct inode *inode)
 {
 	struct ext4_xattr_entry *last;
+	struct ext4_xattr_entry *here = s->here;
 	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
 	int in_inode = i->in_inode;
-	int rc;
+	struct inode *old_ea_inode = NULL;
+	struct inode *new_ea_inode = NULL;
+	int ret;
 
-	/* Compute min_offs and last. */
+	/*
+	 * Optimization for the simple case when old and new values have the
+	 * same padded sizes. Not applicable if the existing value is stored in
+	 * an external inode.
+	 */
+	if (i->value && !s->not_found && !here->e_value_inum &&
+	    EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) ==
+	    EXT4_XATTR_SIZE(i->value_len)) {
+		size_t offs = le16_to_cpu(here->e_value_offs);
+		void *val = s->base + offs;
+		size_t size = EXT4_XATTR_SIZE(i->value_len);
+
+		here->e_value_size = cpu_to_le32(i->value_len);
+		if (i->value == EXT4_ZERO_XATTR_VALUE) {
+			memset(val, 0, size);
+		} else {
+			memcpy(val, i->value, i->value_len);
+			/* Clear padding bytes. */
+			memset(val + i->value_len, 0, size - i->value_len);
+		}
+		return 0;
+	}
+
+	/* Find out min_offs and last to calculate the free space. */
 	last = s->first;
 	for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
 		if (!last->e_value_inum && last->e_value_size) {
@@ -1048,120 +1409,149 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
 	}
 	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
 	if (!s->not_found) {
-		if (!in_inode &&
-		    !s->here->e_value_inum && s->here->e_value_size) {
-			size_t size = le32_to_cpu(s->here->e_value_size);
+		if (!here->e_value_inum && here->e_value_size) {
+			size_t size = le32_to_cpu(here->e_value_size);
 			free += EXT4_XATTR_SIZE(size);
 		}
 		free += EXT4_XATTR_LEN(name_len);
 	}
 	if (i->value) {
-		size_t value_len = EXT4_XATTR_SIZE(i->value_len);
+		size_t value_len = in_inode ? 0 : EXT4_XATTR_SIZE(i->value_len);
 
-		if (in_inode)
-			value_len = 0;
+		if (free < EXT4_XATTR_LEN(name_len) + value_len) {
+			ret = -ENOSPC;
+			goto out;
+		}
+	}
 
-		if (free < EXT4_XATTR_LEN(name_len) + value_len)
-			return -ENOSPC;
+	/*
+	 * Getting access to old and new ea inodes is subject to failures.
+	 * Finish that work before doing any modifications to the xattr data.
+	 */
+	if (!s->not_found && here->e_value_inum) {
+		ret = ext4_xattr_inode_iget(inode,
+		 			    le32_to_cpu(here->e_value_inum),
+		 			    &old_ea_inode);
+		if (ret) {
+			old_ea_inode = NULL;
+			goto out;
+		}
 	}
+	if (i->value && in_inode) {
+		WARN_ON_ONCE(!i->value_len);
 
-	if (i->value && s->not_found) {
-		/* Insert the new name. */
-		size_t size = EXT4_XATTR_LEN(name_len);
-		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
-		memmove((void *)s->here + size, s->here, rest);
-		memset(s->here, 0, size);
-		s->here->e_name_index = i->name_index;
-		s->here->e_name_len = name_len;
-		memcpy(s->here->e_name, i->name, name_len);
-	} else {
-		if (!s->here->e_value_inum && s->here->e_value_size &&
-		    s->here->e_value_offs > 0) {
-			void *first_val = s->base + min_offs;
-			size_t offs = le16_to_cpu(s->here->e_value_offs);
-			void *val = s->base + offs;
-			size_t size = EXT4_XATTR_SIZE(
-				le32_to_cpu(s->here->e_value_size));
-
-			if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
-				/* The old and the new value have the same
-				   size. Just replace. */
-				s->here->e_value_size =
-					cpu_to_le32(i->value_len);
-				if (i->value == EXT4_ZERO_XATTR_VALUE) {
-					memset(val, 0, size);
-				} else {
-					/* Clear pad bytes first. */
-					memset(val + size - EXT4_XATTR_PAD, 0,
-					       EXT4_XATTR_PAD);
-					memcpy(val, i->value, i->value_len);
-				}
-				return 0;
-			}
+		ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
+		if (ret)
+			goto out;
 
-			/* Remove the old value. */
-			memmove(first_val + size, first_val, val - first_val);
-			memset(first_val, 0, size);
-			s->here->e_value_size = 0;
-			s->here->e_value_offs = 0;
-			min_offs += size;
-
-			/* Adjust all value offsets. */
-			last = s->first;
-			while (!IS_LAST_ENTRY(last)) {
-				size_t o = le16_to_cpu(last->e_value_offs);
-				if (!last->e_value_inum &&
-				    last->e_value_size && o < offs)
-					last->e_value_offs =
-						cpu_to_le16(o + size);
-				last = EXT4_XATTR_NEXT(last);
-			}
+		ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
+						     i->value_len,
+						     &new_ea_inode);
+		if (ret) {
+			new_ea_inode = NULL;
+			ext4_xattr_inode_free_quota(inode, i->value_len);
+			goto out;
 		}
-		if (s->here->e_value_inum) {
-			ext4_xattr_inode_unlink(inode,
-					    le32_to_cpu(s->here->e_value_inum));
-			s->here->e_value_inum = 0;
+	}
+
+	if (old_ea_inode) {
+		/* We are ready to release ref count on the old_ea_inode. */
+		ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
+		if (ret) {
+			/* Release newly required ref count on new_ea_inode. */
+			if (new_ea_inode) {
+				int err;
+
+				err = ext4_xattr_inode_dec_ref(handle,
+							       new_ea_inode);
+				if (err)
+					ext4_warning_inode(new_ea_inode,
+						  "dec ref new_ea_inode err=%d",
+						  err);
+				ext4_xattr_inode_free_quota(inode,
+							    i->value_len);
+			}
+			goto out;
 		}
-		if (!i->value) {
-			/* Remove the old name. */
-			size_t size = EXT4_XATTR_LEN(name_len);
-			last = ENTRY((void *)last - size);
-			memmove(s->here, (void *)s->here + size,
-				(void *)last - (void *)s->here + sizeof(__u32));
-			memset(last, 0, size);
+
+		ext4_xattr_inode_free_quota(inode,
+					    le32_to_cpu(here->e_value_size));
+	}
+
+	/* No failures allowed past this point. */
+
+	if (!s->not_found && here->e_value_offs) {
+		/* Remove the old value. */
+		void *first_val = s->base + min_offs;
+		size_t offs = le16_to_cpu(here->e_value_offs);
+		void *val = s->base + offs;
+		size_t size = EXT4_XATTR_SIZE(
+			le32_to_cpu(here->e_value_size));
+
+		memmove(first_val + size, first_val, val - first_val);
+		memset(first_val, 0, size);
+		min_offs += size;
+
+		/* Adjust all value offsets. */
+		last = s->first;
+		while (!IS_LAST_ENTRY(last)) {
+			size_t o = le16_to_cpu(last->e_value_offs);
+			if (!last->e_value_inum &&
+			    last->e_value_size && o < offs)
+				last->e_value_offs =
+					cpu_to_le16(o + size);
+			last = EXT4_XATTR_NEXT(last);
 		}
 	}
 
+	if (!s->not_found && !i->value) {
+		/* Remove old name. */
+		size_t size = EXT4_XATTR_LEN(name_len);
+		last = ENTRY((void *)last - size);
+		memmove(here, (void *)here + size,
+			(void *)last - (void *)here + sizeof(__u32));
+		memset(last, 0, size);
+	} else if (s->not_found && i->value) {
+		/* Insert new name. */
+		size_t size = EXT4_XATTR_LEN(name_len);
+		size_t rest = (void *)last - (void *)here + sizeof(__u32);
+		memmove((void *)here + size, here, rest);
+		memset(here, 0, size);
+		here->e_name_index = i->name_index;
+		here->e_name_len = name_len;
+		memcpy(here->e_name, i->name, name_len);
+	} else {
+		WARN_ON_ONCE(s->not_found || !i->value);
+		/* This is an update, reset value info. */
+		here->e_value_inum = 0;
+		here->e_value_offs = 0;
+		here->e_value_size = 0;
+	}
+
 	if (i->value) {
-		/* Insert the new value. */
+		/* Insert new value. */
 		if (in_inode) {
-			unsigned long ea_ino =
-				le32_to_cpu(s->here->e_value_inum);
-			rc = ext4_xattr_inode_set(handle, inode, &ea_ino,
-						  i->value, i->value_len);
-			if (rc)
-				goto out;
-			s->here->e_value_inum = cpu_to_le32(ea_ino);
-			s->here->e_value_offs = 0;
+			here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
 		} else if (i->value_len) {
 			size_t size = EXT4_XATTR_SIZE(i->value_len);
 			void *val = s->base + min_offs - size;
-			s->here->e_value_offs = cpu_to_le16(min_offs - size);
-			s->here->e_value_inum = 0;
+			here->e_value_offs = cpu_to_le16(min_offs - size);
 			if (i->value == EXT4_ZERO_XATTR_VALUE) {
 				memset(val, 0, size);
 			} else {
-				/* Clear the pad bytes first. */
-				memset(val + size - EXT4_XATTR_PAD, 0,
-				       EXT4_XATTR_PAD);
 				memcpy(val, i->value, i->value_len);
+				/* Clear padding bytes. */
+				memset(val + i->value_len, 0,
+				       size - i->value_len);
 			}
 		}
-		s->here->e_value_size = cpu_to_le32(i->value_len);
+		here->e_value_size = cpu_to_le32(i->value_len);
 	}
-
+	ret = 0;
 out:
-	return rc;
+	iput(old_ea_inode);
+	iput(new_ea_inode);
+	return ret;
 }
 
 struct ext4_xattr_block_find {
@@ -1223,6 +1613,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 	struct mb_cache_entry *ce = NULL;
 	int error = 0;
 	struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
+	struct inode *ea_inode = NULL;
+	size_t old_ea_inode_size = 0;
 
 #define header(x) ((struct ext4_xattr_header *)(x))
 
@@ -1277,6 +1669,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 			header(s->base)->h_refcount = cpu_to_le32(1);
 			s->here = ENTRY(s->base + offset);
 			s->end = s->base + bs->bh->b_size;
+
+			/*
+			 * If existing entry points to an xattr inode, we need
+			 * to prevent ext4_xattr_set_entry() from decrementing
+			 * ref count on it because the reference belongs to the
+			 * original block. In this case, make the entry look
+			 * like it has an empty value.
+			 */
+			if (!s->not_found && s->here->e_value_inum) {
+				/*
+				 * Defer quota free call for previous inode
+				 * until success is guaranteed.
+				 */
+				old_ea_inode_size = le32_to_cpu(
+							s->here->e_value_size);
+				s->here->e_value_inum = 0;
+				s->here->e_value_size = 0;
+			}
 		}
 	} else {
 		/* Allocate a buffer where we construct the new block. */
@@ -1298,6 +1708,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 		goto bad_block;
 	if (error)
 		goto cleanup;
+
+	if (i->value && s->here->e_value_inum) {
+		unsigned int ea_ino;
+
+		/*
+		 * A ref count on ea_inode has been taken as part of the call to
+		 * ext4_xattr_set_entry() above. We would like to drop this
+		 * extra ref but we have to wait until the xattr block is
+		 * initialized and has its own ref count on the ea_inode.
+		 */
+		ea_ino = le32_to_cpu(s->here->e_value_inum);
+		error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+		if (error) {
+			ea_inode = NULL;
+			goto cleanup;
+		}
+	}
+
 	if (!IS_LAST_ENTRY(s->first))
 		ext4_xattr_rehash(header(s->base), s->here);
 
@@ -1408,6 +1836,22 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 						 EXT4_FREE_BLOCKS_METADATA);
 				goto cleanup;
 			}
+			error = ext4_xattr_inode_inc_ref_all(handle, inode,
+						      ENTRY(header(s->base)+1));
+			if (error)
+				goto getblk_failed;
+			if (ea_inode) {
+				/* Drop the extra ref on ea_inode. */
+				error = ext4_xattr_inode_dec_ref(handle,
+								 ea_inode);
+				if (error)
+					ext4_warning_inode(ea_inode,
+							   "dec ref error=%d",
+							   error);
+				iput(ea_inode);
+				ea_inode = NULL;
+			}
+
 			lock_buffer(new_bh);
 			error = ext4_journal_get_create_access(handle, new_bh);
 			if (error) {
@@ -1427,15 +1871,36 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
 		}
 	}
 
+	if (old_ea_inode_size)
+		ext4_xattr_inode_free_quota(inode, old_ea_inode_size);
+
 	/* Update the inode. */
 	EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 
 	/* Drop the previous xattr block. */
-	if (bs->bh && bs->bh != new_bh)
-		ext4_xattr_release_block(handle, inode, bs->bh);
+	if (bs->bh && bs->bh != new_bh) {
+		struct ext4_xattr_inode_array *ea_inode_array = NULL;
+		ext4_xattr_release_block(handle, inode, bs->bh,
+					 &ea_inode_array,
+					 0 /* extra_credits */);
+		ext4_xattr_inode_array_free(ea_inode_array);
+	}
 	error = 0;
 
 cleanup:
+	if (ea_inode) {
+		int error2;
+		error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+		if (error2)
+			ext4_warning_inode(ea_inode, "dec ref error=%d",
+					   error2);
+
+		/* If there was an error, revert the quota charge. */
+		if (error)
+			ext4_xattr_inode_free_quota(inode,
+						    i_size_read(ea_inode));
+		iput(ea_inode);
+	}
 	if (ce)
 		mb_cache_entry_put(ext4_mb_cache, ce);
 	brelse(new_bh);
@@ -1546,6 +2011,117 @@ static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
 	return 0;
 }
 
+struct ext4_xattr_ea_info {
+	__le64 ref_count;	/* number of xattr entry references */
+	__le32 hash;		/* crc32c hash of xattr data */
+	__le32 reserved;	/* reserved, must be 0 */
+};
+
+static int ext4_xattr_inode_init(handle_t *handle, struct inode *ea_inode,
+				 u32 hash)
+{
+	struct ext4_xattr_ea_info ea_info = {
+		.ref_count = cpu_to_le64(1),
+		.hash = cpu_to_le32(hash),
+		.reserved = 0,
+	};
+	struct ext4_xattr_info i = {
+                .name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_EA_INFO,
+		.value = &ea_info,
+		.value_len = sizeof(ea_info),
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int err;
+
+	err = ext4_get_inode_loc(ea_inode, &is.iloc);
+	if (err)
+		return err;
+
+	err = ext4_xattr_ibody_find(ea_inode, &i, &is);
+	if (err)
+		return err;
+
+	return ext4_xattr_ibody_set(handle, ea_inode, &i, &is);
+}
+
+static int ext4_xattr_update_ea_info(struct inode *ea_inode, int ref_change,
+				     u64 *ref_return, u32 *hash)
+{
+	struct ext4_xattr_ea_info ea_info;
+	struct ext4_xattr_info i = {
+                .name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_EA_INFO,
+		.value = &ea_info,
+		.value_len = sizeof(ea_info),
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int err;
+
+	err = ext4_get_inode_loc(ea_inode, &is.iloc);
+	if (err)
+		return err;
+
+	err = ext4_xattr_ibody_find(ea_inode, &i, &is);
+	if (err)
+		return err;
+
+	if (WARN_ON(is.s.not_found) ||
+	    WARN_ON(le32_to_cpu(is.s.here->e_value_size) != sizeof(ea_info)))
+		return -EFSCORRUPTED;
+
+	memcpy(&ea_info,
+	       ((void *)is.s.base) + le16_to_cpu(is.s.here->e_value_offs),
+	       sizeof(ea_info));
+
+	if (hash)
+		*hash = le32_to_cpu(ea_info.hash);
+
+	*ref_return = le64_to_cpu(ea_info.ref_count) + ref_change;
+	ea_info.ref_count = cpu_to_le64(*ref_return);
+
+	return ext4_xattr_set_entry(&i, &is.s, NULL, ea_inode);
+}
+
+static int ext4_xattr_read_ea_hash(struct inode *ea_inode, u32 *hash)
+{
+	struct ext4_xattr_info i = {
+                .name_index = EXT4_XATTR_INDEX_SYSTEM,
+		.name = EXT4_XATTR_SYSTEM_EA_INFO,
+	};
+	struct ext4_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext4_xattr_ea_info *ea_info;
+	void *ptr;
+	int err;
+
+	err = ext4_get_inode_loc(ea_inode, &is.iloc);
+	if (err)
+		return err;
+
+	err = ext4_xattr_ibody_find(ea_inode, &i, &is);
+	if (err)
+		return err;
+
+	if (WARN_ON(is.s.not_found) ||
+	    WARN_ON(le32_to_cpu(is.s.here->e_value_size) != sizeof(*ea_info)))
+		return -EFSCORRUPTED;
+
+	ptr = ((void *)is.s.base) + le16_to_cpu(is.s.here->e_value_offs);
+	ea_info = (struct ext4_xattr_ea_info *)ptr;
+
+	if (WARN_ON(ea_info->reserved != 0))
+		return -EFSCORRUPTED;
+
+	*hash = le32_to_cpu(ea_info->hash);
+	return 0;
+}
+
 static int ext4_xattr_value_same(struct ext4_xattr_search *s,
 				 struct ext4_xattr_info *i)
 {
@@ -1560,6 +2136,22 @@ static int ext4_xattr_value_same(struct ext4_xattr_search *s,
 	return !memcmp(value, i->value, i->value_len);
 }
 
+struct buffer_head *ext4_xattr_get_block(struct inode *inode)
+{
+	struct buffer_head *bh;
+	int error;
+
+	if (!EXT4_I(inode)->i_file_acl)
+		return NULL;
+	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+	if (!bh)
+		return ERR_PTR(-EIO);
+	error = ext4_xattr_check_block(inode, bh);
+	if (error)
+		return ERR_PTR(error);
+	return bh;
+}
+
 /*
  * ext4_xattr_set_handle()
  *
@@ -1602,9 +2194,18 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 
 	/* Check journal credits under write lock. */
 	if (ext4_handle_valid(handle)) {
+		struct buffer_head *bh;
 		int credits;
 
-		credits = ext4_xattr_set_credits(inode, value_len);
+		bh = ext4_xattr_get_block(inode);
+		if (IS_ERR(bh)) {
+			error = PTR_ERR(bh);
+			goto cleanup;
+		}
+
+		credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+		brelse(bh);
+
 		if (!ext4_handle_has_enough_credits(handle, credits)) {
 			error = -ENOSPC;
 			goto cleanup;
@@ -1640,6 +2241,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 		if (flags & XATTR_CREATE)
 			goto cleanup;
 	}
+
 	if (!value) {
 		if (!is.s.not_found)
 			error = ext4_xattr_ibody_set(handle, inode, &i, &is);
@@ -1708,34 +2310,29 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 	return error;
 }
 
-int ext4_xattr_set_credits(struct inode *inode, size_t value_len)
+int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
 {
-	struct super_block *sb = inode->i_sb;
-	int credits;
-
-	if (!EXT4_SB(sb)->s_journal)
-		return 0;
-
-	credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+	struct buffer_head *bh;
+	int err;
 
-	/*
-	 * In case of inline data, we may push out the data to a block,
-	 * so we need to reserve credits for this eventuality
-	 */
-	if (ext4_has_inline_data(inode))
-	        credits += ext4_writepage_trans_blocks(inode) + 1;
+	*credits = 0;
 
-	if (ext4_has_feature_ea_inode(sb)) {
-		int nrblocks = (value_len + sb->s_blocksize - 1) >>
-					sb->s_blocksize_bits;
+	if (!EXT4_SB(inode->i_sb)->s_journal)
+		return 0;
 
-		/* For new inode */
-		credits += EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + 3;
+	down_read(&EXT4_I(inode)->xattr_sem);
 
-		/* For data blocks of EA inode */
-		credits += ext4_meta_trans_blocks(inode, nrblocks, 0);
+	bh = ext4_xattr_get_block(inode);
+	if (IS_ERR(bh)) {
+		err = PTR_ERR(bh);
+	} else {
+		*credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+		brelse(bh);
+		err = 0;
 	}
-	return credits;
+
+	up_read(&EXT4_I(inode)->xattr_sem);
+	return err;
 }
 
 /*
@@ -1760,7 +2357,10 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 		return error;
 
 retry:
-	credits = ext4_xattr_set_credits(inode, value_len);
+	error = ext4_xattr_set_credits(inode, value_len, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle)) {
 		error = PTR_ERR(handle);
@@ -2066,10 +2666,10 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 	return error;
 }
 
-
 #define EIA_INCR 16 /* must be 2^n */
 #define EIA_MASK (EIA_INCR - 1)
-/* Add the large xattr @inode into @ea_inode_array for later deletion.
+
+/* Add the large xattr @inode into @ea_inode_array for deferred iput().
  * If @ea_inode_array is new or full it will be grown and the old
  * contents copied over.
  */
@@ -2114,21 +2714,19 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
  * ext4_xattr_delete_inode()
  *
  * Free extended attribute resources associated with this inode. Traverse
- * all entries and unlink any xattr inodes associated with this inode. This
- * is called immediately before an inode is freed. We have exclusive
- * access to the inode. If an orphan inode is deleted it will also delete any
- * xattr block and all xattr inodes. They are checked by ext4_xattr_inode_iget()
- * to ensure they belong to the parent inode and were not deleted already.
+ * all entries and decrement reference on any xattr inodes associated with this
+ * inode. This is called immediately before an inode is freed. We have exclusive
+ * access to the inode. If an orphan inode is deleted it will also release its
+ * references on xattr block and xattr inodes.
  */
-int
-ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-			struct ext4_xattr_inode_array **ea_inode_array,
-			int extra_credits)
+int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+			    struct ext4_xattr_inode_array **ea_inode_array,
+			    int extra_credits)
 {
 	struct buffer_head *bh = NULL;
 	struct ext4_xattr_ibody_header *header;
-	struct ext4_inode *raw_inode;
 	struct ext4_iloc iloc = { .bh = NULL };
+	struct ext4_xattr_entry *entry;
 	int error;
 
 	error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
@@ -2140,66 +2738,71 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 		goto cleanup;
 	}
 
-	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
-		goto delete_external_ea;
-
-	error = ext4_get_inode_loc(inode, &iloc);
-	if (error)
-		goto cleanup;
+	if (ext4_has_feature_ea_inode(inode->i_sb) &&
+	    ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 
-	error = ext4_journal_get_write_access(handle, iloc.bh);
-	if (error)
-		goto cleanup;
+		error = ext4_get_inode_loc(inode, &iloc);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
+			goto cleanup;
+		}
 
-	raw_inode = ext4_raw_inode(&iloc);
-	header = IHDR(inode, raw_inode);
-	ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),
-				    false /* block_csum */, ea_inode_array,
-				    extra_credits);
+		error = ext4_journal_get_write_access(handle, iloc.bh);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "write access (error %d)",
+					 error);
+			goto cleanup;
+		}
 
-delete_external_ea:
-	if (!EXT4_I(inode)->i_file_acl) {
-		error = 0;
-		goto cleanup;
-	}
-	bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
-	if (!bh) {
-		EXT4_ERROR_INODE(inode, "block %llu read error",
-				 EXT4_I(inode)->i_file_acl);
-		error = -EIO;
-		goto cleanup;
-	}
-	if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
-	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
-		EXT4_ERROR_INODE(inode, "bad block %llu",
-				 EXT4_I(inode)->i_file_acl);
-		error = -EFSCORRUPTED;
-		goto cleanup;
+		header = IHDR(inode, ext4_raw_inode(&iloc));
+		if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+			ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
+						     IFIRST(header),
+						     false /* block_csum */,
+						     ea_inode_array,
+						     extra_credits,
+						     false /* skip_quota */);
 	}
 
-	if (ext4_has_feature_ea_inode(inode->i_sb)) {
-		error = ext4_journal_get_write_access(handle, bh);
-		if (error) {
-			EXT4_ERROR_INODE(inode, "write access %llu",
+	if (EXT4_I(inode)->i_file_acl) {
+		bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+		if (!bh) {
+			EXT4_ERROR_INODE(inode, "block %llu read error",
 					 EXT4_I(inode)->i_file_acl);
+			error = -EIO;
+			goto cleanup;
+		}
+		error = ext4_xattr_check_block(inode, bh);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
+					 EXT4_I(inode)->i_file_acl, error);
 			goto cleanup;
 		}
-		ext4_xattr_inode_remove_all(handle, inode, bh,
-					    BFIRST(bh),
-					    true /* block_csum */,
-					    ea_inode_array,
-					    extra_credits);
-	}
 
-	ext4_xattr_release_block(handle, inode, bh);
-	/* Update i_file_acl within the same transaction that releases block. */
-	EXT4_I(inode)->i_file_acl = 0;
-	error = ext4_mark_inode_dirty(handle, inode);
-	if (error) {
-		EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
-				 error);
-		goto cleanup;
+		if (ext4_has_feature_ea_inode(inode->i_sb)) {
+			for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+			     entry = EXT4_XATTR_NEXT(entry))
+				if (entry->e_value_inum)
+					ext4_xattr_inode_free_quota(inode,
+					      le32_to_cpu(entry->e_value_size));
+
+		}
+
+		ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
+					 extra_credits);
+		/*
+		 * Update i_file_acl value in the same transaction that releases
+		 * block.
+		 */
+		EXT4_I(inode)->i_file_acl = 0;
+		error = ext4_mark_inode_dirty(handle, inode);
+		if (error) {
+			EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+					 error);
+			goto cleanup;
+		}
 	}
+	error = 0;
 cleanup:
 	brelse(iloc.bh);
 	brelse(bh);
@@ -2208,17 +2811,13 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 
 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
 {
-	struct inode	*ea_inode;
-	int		idx = 0;
+	int idx;
 
 	if (ea_inode_array == NULL)
 		return;
 
-	for (; idx < ea_inode_array->count; ++idx) {
-		ea_inode = ea_inode_array->inodes[idx];
-		clear_nlink(ea_inode);
-		iput(ea_inode);
-	}
+	for (idx = 0; idx < ea_inode_array->count; ++idx)
+		iput(ea_inode_array->inodes[idx]);
 	kfree(ea_inode_array);
 }
 
fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -70,19 +70,6 @@ struct ext4_xattr_entry {
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
 /*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
-/*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
 */
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 77a5b99d8f92..7dfdca822ccb 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.0.219.gdb65acc882-goog
#50 lore raw

Re: [PATCH v2 27/28] ext4: xattr inode deduplication

Quoted 2 lines

Hmm... normally we'd supply sbi->s_csum_seed as the second argument so that the metadata checksum value also has the fs uuid stamped into it.

I have thought about using sbi->s_csum_seed and was a little hesitant because it involves adding more complexity to e2fsprogs to handle cases like changing uuid or turning off metadata_csum. After thinking more about this, I think it is doable.

Quoted 4 lines

Even if you dismiss that, we usually follow the convention of initializing the crc32c calculation with (~0U), not (0U), to strengthen crc32c's ability to detect zeroes being injected at the start of the stream.

Agreed, using ~0 is definitely better than 0.

#51 lore raw

Re: [PATCH v2 27/28] ext4: xattr inode deduplication

Quoted 7 lines · Tahsin Erdogan
Quoted 2 lines

Hmm... normally we'd supply sbi->s_csum_seed as the second argument so that the metadata checksum value also has the fs uuid stamped into it.

I have thought about using sbi->s_csum_seed and was a little hesitant because it involves adding more complexity to e2fsprogs to handle cases like changing uuid or turning off metadata_csum. After thinking more about this, I think it is doable.

e2fsprogs already has code to walk the fs to rewrite/remove checksums, so it shouldn't be too much effort to tap into that to rewrite the ea_info hash.

Quoted 6 lines
Quoted 4 lines

Even if you dismiss that, we usually follow the convention of initializing the crc32c calculation with (~0U), not (0U), to strengthen crc32c's ability to detect zeroes being injected at the start of the stream.

Agreed, using ~0 is definitely better than 0.

--D

#52 lore raw

PATCH v3 27/28 ext4: xattr inode deduplication

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v3:
- use s_csum_seed for hash calculations when available
- return error on stored vs calculated hash mismatch

v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |   22 +-
 fs/ext4/inode.c |    9 +-
 fs/ext4/super.c |   25 +-
 fs/ext4/xattr.c | 1081 ++++++++++++++++++++++++++++++++++++++++++-------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 896 insertions(+), 272 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +14 -8
index d79d8d7bee88..7ceb1f81e4b8 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
@@ -2709,19 +2714,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
 				    ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-	return ext4_has_feature_gdt_csum(sb) ||
-	       EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
 	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
 		     !EXT4_SB(sb)->s_chksum_driver);
 
-	return (EXT4_SB(sb)->s_chksum_driver != NULL);
+	return ext4_has_feature_metadata_csum(sb) &&
+	       (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +8 -1
index 4d6936f0d8a4..6f5872197d6c 100644
@@ -4843,8 +4843,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/super.c +23 -2
index b02a23ec92ca..9fcd29e21dc7 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Load the checksum driver */
-	if (ext4_has_feature_metadata_csum(sb)) {
+	if (ext4_has_feature_metadata_csum(sb) ||
+	    ext4_has_feature_ea_inode(sb)) {
 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
 		if (IS_ERR(sbi->s_chksum_driver)) {
 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -4067,6 +4075,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4313,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +840 -241

1,385 lines not on this page · raw message

fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -69,19 +69,6 @@ struct ext4_xattr_entry {
 		EXT4_I(inode)->i_extra_isize))
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
-/*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
 /*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 77a5b99d8f92..7dfdca822ccb 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.0.506.g27d5fe0cd-goog
#53 lore raw

PATCH v4 27/28 ext4: xattr inode deduplication

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v4:
- eliminated xattr entry in the xattr inode to avoid complexity and recursion in xattr update path. Now the ref count and hash are stored in i_[c/m/a]time.tv_sec fields.
- some clean up in ext4_xattr_set_entry() to reduce code duplication and complexity

v3:
- use s_csum_seed for hash calculations when available
- return error on stored vs calculated hash mismatch

v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |   22 +-
 fs/ext4/inode.c |    9 +-
 fs/ext4/super.c |   25 +-
 fs/ext4/xattr.c | 1000 +++++++++++++++++++++++++++++++++++++++++--------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 806 insertions(+), 281 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +14 -8
index d79d8d7bee88..7ceb1f81e4b8 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
@@ -2709,19 +2714,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
 				    ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-	return ext4_has_feature_gdt_csum(sb) ||
-	       EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
 	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
 		     !EXT4_SB(sb)->s_chksum_driver);
 
-	return (EXT4_SB(sb)->s_chksum_driver != NULL);
+	return ext4_has_feature_metadata_csum(sb) &&
+	       (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +8 -1
index 4d6936f0d8a4..6f5872197d6c 100644
@@ -4843,8 +4843,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
fs/ext4/super.c +23 -2
index b02a23ec92ca..9fcd29e21dc7 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Load the checksum driver */
-	if (ext4_has_feature_metadata_csum(sb)) {
+	if (ext4_has_feature_metadata_csum(sb) ||
+	    ext4_has_feature_ea_inode(sb)) {
 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
 		if (IS_ERR(sbi->s_chksum_driver)) {
 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -4067,6 +4075,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4313,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +750 -250

1,273 lines not on this page · raw message

fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -69,19 +69,6 @@ struct ext4_xattr_entry {
 		EXT4_I(inode)->i_extra_isize))
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
-/*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
 /*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 77a5b99d8f92..7dfdca822ccb 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.1.508.gb3defc5cc-goog
#54 lore raw

Re: [PATCH v4 27/28] ext4: xattr inode deduplication

[reduced CC list to linux-ext4]

Quoted 55 lines · Tahsin Erdogan

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v4:
- eliminated xattr entry in the xattr inode to avoid complexity and recursion in xattr update path. Now the ref count and hash are stored in i_[c/m/a]time.tv_sec fields.
- some clean up in ext4_xattr_set_entry() to reduce code duplication and complexity

v3:
- use s_csum_seed for hash calculations when available
- return error on stored vs calculated hash mismatch

v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

fs/ext4/acl.c   |    5 +-
fs/ext4/ext4.h  |   22 +-
fs/ext4/inode.c |    9 +-
fs/ext4/super.c |   25 +-
fs/ext4/xattr.c | 1000 +++++++++++++++++++++++++++++++++++++++++--------------
fs/ext4/xattr.h |   17 +-
fs/mbcache.c    |    9 +-
7 files changed, 806 insertions(+), 281 deletions(-)
fs/ext4/super.c +0 -0
index b02a23ec92ca..9fcd29e21dc7 100644
@@ -4067,6 +4075,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;

fs/ext4/super.c static int ext4_fill_super(struct super_block *sb, void *data, int silent) · line 4085

Quoted 10 lines
fs/ext4/super.c +8 -0
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}

It would be preferable to allow a mount option like "no_mbcache" to disable the use of shared xattrs. In the Lustre case at least, there will never be shared large xattrs, and we've had a bunch of performance issues with mbcache due to lock contention among many server threads doing concurrent lookups and inserting many thousands of unique entries into the cache.

fs/ext4/xattr.c ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, · line 290

Quoted 13 lines
fs/ext4/xattr.c +5 -0
index abc7d5f84e5f..2f9bcafd9aed 100644
@@ -280,6 +283,34 @@ ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
 	return cmp ? -ENODATA : 0;
 }
 
+static u32
+ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
+{
+	return ext4_chksum(sbi, sbi->s_csum_seed ?: ~0, buffer, size);
+}

This should follow the existing convention of always using s_csum_seed to seed the checksum, and change ext4_fill_super() to initialize s_csum_seed to ~0 if ext4_has_metadata_csum() is false, or always use the same value regardless of whether ext4_has_metadata_csum() is set or not.

fs/ext4/xattr.c ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, · line 296

Quoted 5 lines
fs/ext4/xattr.c +5 -0
+static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
+{
+	return ((u64)ea_inode->i_ctime.tv_sec << 32) |
+	       ((u32)ea_inode->i_mtime.tv_sec);
+}

If it really necessary to have more than 2^32 references on a single shared inode then it would be better to avoid the re-use of i_mtime, which breaks the backref for unshared xattrs, and using i_size isn't enough of a guarantee that this is the correct parent inode in case of on-disk corruption.

If you think that > 2^32 references to a single xattr is really needed, you can use i_ctime_extra, since this will almost certainly only be used on ext4 filesystems with 256-byte or larger inodes. It is highly unlikely that there are filesystems with multi-billions of shared xattrs that are ext2-formatted.

This allows for a period of transition between existing single-user xattr inodes (which use i_mtime for the parent back-ref) and the shared xattr inodes, instead of requiring a full e2fsck when upgrading from an older version of xattr inodes to a new kernel, and then doing the same if there is a need to downgrade again.

Quoted 33 lines
fs/ext4/xattr.c +19 -2
+static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
+{
+	ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
+	ea_inode->i_mtime.tv_sec = (u32)ref_count;
+}
+
+static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
+{
+	return (u32)ea_inode->i_atime.tv_sec;
+}
+
+static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
+{
+	ea_inode->i_atime.tv_sec = hash;
+}
+
 /*
 * Read the EA value from an inode.
 */
@@ -298,13 +331,24 @@ static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 		if (!bh)
 			return -EFSCORRUPTED;
 
-		memcpy(buf, bh->b_data, csize);
+		memcpy(copy_pos, bh->b_data, csize);
 		brelse(bh);
 
-		buf += csize;
+		copy_pos += csize;
 		block += 1;
 		copied += csize;
 	}
+

fs/ext4/xattr.c static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size) · line 351

Quoted 10 lines
fs/ext4/xattr.c +10 -0
+	calc_hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buf, size);
+
+	/* Verify stored hash matches calculated hash. */
+	stored_hash = ext4_xattr_inode_get_hash(ea_inode);
+	if (calc_hash != stored_hash) {
+		ext4_warning_inode(ea_inode,
+			"EA inode calc_hash=%#x does not match stored_hash=%#x",
+			calc_hash, stored_hash);
+		return -EFSCORRUPTED;
+	}

Should this be contingent on ext4_has_metadata_csum() feature being enabled, or alternately check if EXT4_XATTR_INODE_GET_PARENT() and i_generation match before returning an error. This will allow a smooth transition from existing filesystems that do not store the hash, but have only a single-use xattr inode with a parent backref.

fs/ext4/xattr.c static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino, · line 338

Quoted 11 lines
fs/ext4/xattr.c +0 -7
@@ -329,14 +373,6 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
 		goto error;
 	}
 
-	if (EXT4_XATTR_INODE_GET_PARENT(inode) != parent->i_ino ||
-	    inode->i_generation != parent->i_generation) {
-		ext4_error(parent->i_sb, "Backpointer from EA inode %lu "
-			   "to parent is invalid.", ea_ino);
-		err = -EINVAL;
-		goto error;
-	}

This check here should be moved up to ext4_xattr_inode_read().

Quoted 19 lines
fs/ext4/xattr.c +18 -0
+static int __ext4_xattr_set_credits(struct super_block *sb,
 
+				    struct buffer_head *block_bh,
+				    size_t value_len)
+{
+	int credits;
+	int blocks;
+
+	/*
+	 * 1) Owner inode update
+	 * 2) Ref count update on old xattr block
+	 * 3) new xattr block
+	 * 4) block bitmap update for new xattr block
+	 * 5) group descriptor for new xattr block
+	 */
+	credits = 5;
+
+	/* We are done if ea_inode feature is not enabled. */
+	if (!ext4_has_feature_ea_inode(sb))

fs/ext4/xattr.c static void ext4_xattr_update_super_block(handle_t *handle, · line 769

Quoted 10 lines
fs/ext4/xattr.c +10 -0
+		return credits;
+
+	/* New ea_inode, inode map, block bitmap, group descriptor. */
+	credits += 4;
+
+	/* Data blocks. */
+	blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+
+	/* Indirection block. */
+	blocks += 1;

Strictly speaking, this is only needed "if (blocks > EXT4_NDIR_BLOCKS)".

Quoted 17 lines
fs/ext4/xattr.c +17 -0
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Blocks themselves. */
+	credits += blocks;
+
+	/* Dereference ea_inode holding old xattr value.
+	 * Old ea_inode, inode map, block bitmap, group descriptor.
+	 */
+	credits += 4;
+
+	/* Data blocks for old ea_inode. */
+	blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+
+	/* Indirection block for old ea_inode. */
+	blocks += 1;

fs/ext4/xattr.c static void ext4_xattr_update_super_block(handle_t *handle, · line 796

Quoted 10 lines
fs/ext4/xattr.c +10 -0
+
+	/* Block bitmap and group descriptor updates for each block. */
+	credits += blocks * 2;
+
+	/* Quota updates. */
+	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
+
+	/* We may need to clone the existing xattr block in which case we need
+	 * to increment ref counts for existing ea_inodes referenced by it.
+	 */

Just to clarify here, in the case of cloning an existing xattr block, are the refcounts being _incremented_ or _decremented_ on the existing ea_inodes? I'm trying to figure out if we really need to have credits for both old and new xattr inodes, as well as these additional credits. Since this is reserving about 110 blocks for every setxattr, this can add significant pressure on the journal if there are lots of threads creating files and/or setting xattrs.

Quoted 12 lines
fs/ext4/xattr.c +10 -0
+	if (block_bh) {
+		struct ext4_xattr_entry *entry = BFIRST(block_bh);
+
+		for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				/* Ref count update on ea_inode. */
+				credits += 1;
+	}
+	return credits;
+}

fs/ext4/xattr.c static struct inode *ext4_xattr_inode_create(handle_t +static struct inode * · line 1264

Quoted 8 lines
fs/ext4/xattr.c +6 -0
@@ -965,67 +1257,121 @@ static struct inode *ext4_xattr_inode_create(handle_t	+static struct inode *
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+			    size_t value_len, u32 hash)
 {
+	struct inode *ea_inode;
+	struct mb_cache_entry *ce;
+	struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+	void *ea_data = NULL;
 	int err;

This function should just return NULL if ea_inode_cache is NULL (e.g. in the case of "no_mbcache" mount option).

Quoted 76 lines
fs/ext4/xattr.c +53 -7
+	ce = mb_cache_entry_find_first(ea_inode_cache, hash);
+	while (ce) {
+		ea_inode = ext4_iget(inode->i_sb, ce->e_value);
+		if (IS_ERR(ea_inode)) {
+			ea_inode = NULL;
+			goto next;
+		}
 
+		if (is_bad_inode(ea_inode) ||
+		    !(EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) ||
+		    i_size_read(ea_inode) != value_len)
+			goto next;
 
+		if (!ea_data)
+			ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
+
+		if (!ea_data) {
+			iput(ea_inode);
+			return NULL;
+		}
+
+		err = ext4_xattr_inode_read(ea_inode, ea_data, value_len);
+		if (unlikely(err))
+			goto next;
+
+		if (!memcmp(value, ea_data, value_len)) {
+			mb_cache_entry_touch(ea_inode_cache, ce);
+			mb_cache_entry_put(ea_inode_cache, ce);
+			kvfree(ea_data);
+			return ea_inode;
+		}
+next:
+		iput(ea_inode);
+		ce = mb_cache_entry_find_next(ea_inode_cache, ce);
+	}
+	kvfree(ea_data);
+	return NULL;
 }
 
 /*
 * Add value of the EA in an inode.
 */
-static int ext4_xattr_inode_set(handle_t *handle, struct inode *inode,
-				unsigned long *ea_ino, const void *value,
-				size_t value_len)
+static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
+					  const void *value, size_t value_len,
+					  struct inode **ret_inode)
 {
 	struct inode *ea_inode;
+	u32 hash;
 	int err;
 
+	hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
+	ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
+	if (ea_inode) {
+		err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+		if (err) {
+			iput(ea_inode);
+			return err;
+		}
+
+		*ret_inode = ea_inode;
+		return 0;
+	}
+
 	/* Create an inode for the EA value */
-	ea_inode = ext4_xattr_inode_create(handle, inode);
+	ea_inode = ext4_xattr_inode_create(handle, inode, hash);
 	if (IS_ERR(ea_inode))
 		return PTR_ERR(ea_inode);
 
 	err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
-	if (err)
-		clear_nlink(ea_inode);
-	else

fs/ext4/xattr.c static struct inode *ext4_xattr_inode_create(handle_t *handle, · line 1371

Quoted 10 lines
fs/ext4/xattr.c +7 -2
-		*ea_ino = ea_inode->i_ino;
+	if (err) {
+		ext4_xattr_inode_dec_ref(handle, ea_inode);
+		iput(ea_inode);
+		return err;
+	}
 
-	iput(ea_inode);
+	mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
+			      ea_inode->i_ino, true /* reusable */);

Should skip mb_cache if EA_INODE_CACHE(inode) is NULL, or have a wrapper like ext4_xattr_inode_cache_insert() to match ext4_xattr_inode_cache_find() that does the same.

Cheers, Andreas

#55 lore raw

PATCH v5 27/28 ext4: xattr inode deduplication

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v5:
- made ext4_meta_trans_blocks() static again since there are no remaining users outside of inode.c
- initialize sbi->s_csum_seed when ea_inode feature is enabled
- use l_i_version to hold lower 32 bits of the xattr ref count. This avoids clashes with old implementations which use i_mtime. Since l_i_version is not available in HURD_COMPAT mode, fail mount request when both ea_inode feature and HURD_COMPAT are set.
- when hash validation fails, fall back to old implementation which has a backref to parent.
- fixed checkpatch.pl warning about using unsigned alone

v4:
- eliminated xattr entry in the xattr inode to avoid complexity and recursion in xattr update path. Now the ref count and hash are stored in i_[c/m/a]time.tv_sec fields.
- some clean up in ext4_xattr_set_entry() to reduce code duplication and complexity

v3:
- use s_csum_seed for hash calculations when available
- return error on stored vs calculated hash mismatch

v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |   23 +-
 fs/ext4/inode.c |   13 +-
 fs/ext4/super.c |   37 +-
 fs/ext4/xattr.c | 1038 +++++++++++++++++++++++++++++++++++++++++--------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 848 insertions(+), 294 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
 	if (error)
 		return error;
 retry:
-	credits = ext4_xattr_set_credits(inode, acl_size);
+	error = ext4_xattr_set_credits(inode, acl_size, &credits);
+	if (error)
+		return error;
+
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
fs/ext4/ext4.h +14 -9
index d79d8d7bee88..59e9488c4876 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;
 	spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
 	/* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
 	return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+	return IS_NOQUOTA(inode) &&
+	       !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
@@ -2482,7 +2487,6 @@ extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
 extern void ext4_set_inode_flags(struct inode *);
 extern int ext4_alloc_da_blocks(struct inode *inode);
 extern void ext4_set_aops(struct inode *inode);
-extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int chunk);
 extern int ext4_writepage_trans_blocks(struct inode *);
 extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
 extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
@@ -2709,19 +2713,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
 				    ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-	return ext4_has_feature_gdt_csum(sb) ||
-	       EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
 	WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
 		     !EXT4_SB(sb)->s_chksum_driver);
 
-	return (EXT4_SB(sb)->s_chksum_driver != NULL);
+	return ext4_has_feature_metadata_csum(sb) &&
+	       (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+	return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +11 -2
index cd007f9757d1..ea95bd9eab81 100644
@@ -139,6 +139,8 @@ static void ext4_invalidatepage(struct page *page, unsigned int offset,
 				unsigned int length);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+				  int pextents);
 
 /*
  * Test whether an inode is a fast symlink.
@@ -4843,8 +4845,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 	}
 	brelse(iloc.bh);
 	ext4_set_inode_flags(inode);
-	if (ei->i_flags & EXT4_EA_INODE_FL)
+
+	if (ei->i_flags & EXT4_EA_INODE_FL) {
 		ext4_xattr_inode_set_class(inode);
+
+		inode_lock(inode);
+		inode->i_flags |= S_NOQUOTA;
+		inode_unlock(inode);
+	}
+
 	unlock_new_inode(inode);
 	return inode;
 
@@ -5503,7 +5512,7 @@ static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
  *
  * Also account for superblock, inode, quota and xattr blocks
  */
-int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 				  int pextents)
 {
 	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
fs/ext4/super.c +34 -3
index b02a23ec92ca..2bfacd737bb6 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
 		invalidate_bdev(sbi->journal_bdev);
 		ext4_blkdev_remove(sbi);
 	}
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
 	if (res)
 		return res;
 retry:
-	credits = ext4_xattr_set_credits(inode, len);
+	res = ext4_xattr_set_credits(inode, len, &credits);
+	if (res)
+		return res;
+
 	handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Load the checksum driver */
-	if (ext4_has_feature_metadata_csum(sb)) {
+	if (ext4_has_feature_metadata_csum(sb) ||
+	    ext4_has_feature_ea_inode(sb)) {
 		sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
 		if (IS_ERR(sbi->s_chksum_driver)) {
 			ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -3467,7 +3475,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	/* Precompute checksum seed for all metadata */
 	if (ext4_has_feature_csum_seed(sb))
 		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
-	else if (ext4_has_metadata_csum(sb))
+	else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
 					       sizeof(es->s_uuid));
 
@@ -3597,6 +3605,16 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 				 "The Hurd can't support 64-bit file systems");
 			goto failed_mount;
 		}
+
+		/*
+		 * ea_inode feature uses l_i_version field which is not
+		 * available in HURD_COMPAT mode.
+		 */
+		if (ext4_has_feature_ea_inode(sb)) {
+			ext4_msg(sb, KERN_ERR,
+				 "ea_inode feature is not supported for Hurd");
+			goto failed_mount;
+		}
 	}
 
 	if (IS_EXT2_SB(sb)) {
@@ -4067,6 +4085,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount_wq;
 	}
 
+	if (ext4_has_feature_ea_inode(sb)) {
+		sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+		if (!sbi->s_ea_inode_cache) {
+			ext4_msg(sb, KERN_ERR,
+				 "Failed to create an s_ea_inode_cache");
+			goto failed_mount_wq;
+		}
+	}
+
 	if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
 	    (blocksize != PAGE_SIZE)) {
 		ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4323,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	if (EXT4_SB(sb)->rsv_conversion_wq)
 		destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+	if (sbi->s_ea_inode_cache) {
+		ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+		sbi->s_ea_inode_cache = NULL;
+	}
 	if (sbi->s_mb_cache) {
 		ext4_xattr_destroy_cache(sbi->s_mb_cache);
 		sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +778 -260

1,330 lines not on this page · raw message

fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -69,19 +69,6 @@ struct ext4_xattr_entry {
 		EXT4_I(inode)->i_extra_isize))
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
-/*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
 /*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+				  int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 				   struct ext4_xattr_inode_array **array,
 				   int extra_credits);
fs/mbcache.c +5 -4
index 45a8d52dc991..d818fd236787 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
Signature · 1 line
2.13.1.518.g3df882009-goog
#56 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

Thanks Andreas for the feedback. Please see my responses below:

Quoted 5 lines

It would be preferable to allow a mount option like "no_mbcache" to disable the use of shared xattrs. In the Lustre case at least, there will never be shared large xattrs, and we've had a bunch of performance issues with mbcache due to lock contention among many server threads doing concurrent lookups and inserting many thousands of unique entries into the cache.

I have put nombcache mount option in a separate patch ("[PATCH 32/32]
ext4: add nombcache mount option"). I have named it nombcache instead of no_mbcache to be consistent with other no* options. Let me know if you prefer no_mbcache as the option name.

Quoted 4 lines

This should follow the existing convention of always using s_csum_seed to seed the checksum, and change ext4_fill_super() to initialize s_csum_seed to ~0 if ext4_has_metadata_csum() is false, or always use the same value regardless of whether ext4_has_metadata_csum() is set or not.

Done.

Quoted 4 lines

If it really necessary to have more than 2^32 references on a single shared inode then it would be better to avoid the re-use of i_mtime, which breaks the backref for unshared xattrs, and using i_size isn't enough of a guarantee that this is the correct parent inode in case of on-disk corruption.

I have now moved the lower 32bits of ref count from i_mtime to l_i_version.

Quoted 5 lines

Should this be contingent on ext4_has_metadata_csum() feature being enabled, or alternately check if EXT4_XATTR_INODE_GET_PARENT() and i_generation match before returning an error. This will allow a smooth transition from existing filesystems that do not store the hash, but have only a single-use xattr inode with a parent backref.

I updated hash validation to fallback to parent backref check for backward compatibility.

Quoted 4 lines

Review

Quoted 2 lines
(quoted diff) +2 -0
+     /* Indirection block. */
+     blocks += 1;

Strictly speaking, this is only needed "if (blocks > EXT4_NDIR_BLOCKS)".

Ack. I didn't think it was worth going through exact calculation in this case, let me know if you see value in doing that
I also updated the comment to mention extents.

Quoted 10 lines

fs/ext4/xattr.c static void ext4_xattr_update_super_block(handle_t *handle, · line 820

Quoted 3 lines
fs/ext4/xattr.c +3 -0
+     /* We may need to clone the existing xattr block in which case we need
+      * to increment ref counts for existing ea_inodes referenced by it.
+      */

Just to clarify here, in the case of cloning an existing xattr block, are the refcounts being _incremented_ or _decremented_ on the existing ea_inodes? I'm trying to figure out if we really need to have credits for both old and new xattr inodes, as well as these additional credits. Since this is reserving about 110 blocks for every setxattr, this can add significant pressure on the journal if there are lots of threads creating files and/or setting xattrs.

Cloning causes incrementing xattr inode references.

Quoted 11 lines

fs/ext4/xattr.c static struct inode *ext4_xattr_inode_create(handle_t *handle, · line 1362

Quoted 8 lines
fs/ext4/xattr.c +2 -0
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+                         size_t value_len, u32 hash)

{

fs/ext4/xattr.c +4 -0
+     struct inode *ea_inode;
+     struct mb_cache_entry *ce;
+     struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+     void *ea_data = NULL;
      int err;

This function should just return NULL if ea_inode_cache is NULL (e.g. in the case of "no_mbcache" mount option).

Done in later patch ("[PATCH 32/32] ext4: add nombcache mount option")

Quoted 3 lines

Should skip mb_cache if EA_INODE_CACHE(inode) is NULL, or have a wrapper like ext4_xattr_inode_cache_insert() to match ext4_xattr_inode_cache_find() that does the same.

Added skip in patch ("[PATCH 32/32] ext4: add nombcache mount option")

Quoted 1,689 lines · Tahsin Erdogan

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v5:
- made ext4_meta_trans_blocks() static again since there are no remaining users outside of inode.c
- initialize sbi->s_csum_seed when ea_inode feature is enabled
- use l_i_version to hold lower 32 bits of the xattr ref count. This avoids clashes with old implementations which use i_mtime. Since l_i_version is not available in HURD_COMPAT mode, fail mount request when both ea_inode feature and HURD_COMPAT are set.
- when hash validation fails, fall back to old implementation which has a backref to parent.
- fixed checkpatch.pl warning about using unsigned alone

v4:
- eliminated xattr entry in the xattr inode to avoid complexity and recursion in xattr update path. Now the ref count and hash are stored in i_[c/m/a]time.tv_sec fields.
- some clean up in ext4_xattr_set_entry() to reduce code duplication and complexity

v3:
- use s_csum_seed for hash calculations when available
- return error on stored vs calculated hash mismatch

v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

 fs/ext4/acl.c   |    5 +-
 fs/ext4/ext4.h  |   23 +-
 fs/ext4/inode.c |   13 +-
 fs/ext4/super.c |   37 +-
 fs/ext4/xattr.c | 1038 +++++++++++++++++++++++++++++++++++++++++--------------
 fs/ext4/xattr.h |   17 +-
 fs/mbcache.c    |    9 +-
 7 files changed, 848 insertions(+), 294 deletions(-)
fs/ext4/acl.c +4 -1
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
        if (error)
                return error;
 retry:
-       credits = ext4_xattr_set_credits(inode, acl_size);
+       error = ext4_xattr_set_credits(inode, acl_size, &credits);
+       if (error)
+               return error;
+
        handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
fs/ext4/ext4.h +14 -9
index d79d8d7bee88..59e9488c4876 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
        long s_es_nr_inode;
        struct ext4_es_stats s_es_stats;
        struct mb_cache *s_mb_cache;
+       struct mb_cache *s_ea_inode_cache;
        spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
        /* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
        return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+       return IS_NOQUOTA(inode) &&
+              !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
  * This structure is stuffed into the struct file's private_data field
@@ -2482,7 +2487,6 @@ extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
 extern void ext4_set_inode_flags(struct inode *);
 extern int ext4_alloc_da_blocks(struct inode *inode);
 extern void ext4_set_aops(struct inode *inode);
-extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int chunk);
 extern int ext4_writepage_trans_blocks(struct inode *);
 extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
 extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
@@ -2709,19 +2713,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
                                    ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-       return ext4_has_feature_gdt_csum(sb) ||
-              EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
        WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
                     !EXT4_SB(sb)->s_chksum_driver);
 
-       return (EXT4_SB(sb)->s_chksum_driver != NULL);
+       return ext4_has_feature_metadata_csum(sb) &&
+              (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+       return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
        return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +11 -2
index cd007f9757d1..ea95bd9eab81 100644
@@ -139,6 +139,8 @@ static void ext4_invalidatepage(struct page *page, unsigned int offset,
                                unsigned int length);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+                                 int pextents);
 
 /*
  * Test whether an inode is a fast symlink.
@@ -4843,8 +4845,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
        }
        brelse(iloc.bh);
        ext4_set_inode_flags(inode);
-       if (ei->i_flags & EXT4_EA_INODE_FL)
+
+       if (ei->i_flags & EXT4_EA_INODE_FL) {
                ext4_xattr_inode_set_class(inode);
+
+               inode_lock(inode);
+               inode->i_flags |= S_NOQUOTA;
+               inode_unlock(inode);
+       }
+
        unlock_new_inode(inode);
        return inode;
 
@@ -5503,7 +5512,7 @@ static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
  *
  * Also account for superblock, inode, quota and xattr blocks
  */
-int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
                                  int pextents)
 {
        ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
fs/ext4/super.c +34 -3
index b02a23ec92ca..2bfacd737bb6 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
                invalidate_bdev(sbi->journal_bdev);
                ext4_blkdev_remove(sbi);
        }
+       if (sbi->s_ea_inode_cache) {
+               ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+               sbi->s_ea_inode_cache = NULL;
+       }
        if (sbi->s_mb_cache) {
                ext4_xattr_destroy_cache(sbi->s_mb_cache);
                sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
        if (res)
                return res;
 retry:
-       credits = ext4_xattr_set_credits(inode, len);
+       res = ext4_xattr_set_credits(inode, len, &credits);
+       if (res)
+               return res;
+
        handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
        if (IS_ERR(handle))
                return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        }
 
        /* Load the checksum driver */
-       if (ext4_has_feature_metadata_csum(sb)) {
+       if (ext4_has_feature_metadata_csum(sb) ||
+           ext4_has_feature_ea_inode(sb)) {
                sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
                if (IS_ERR(sbi->s_chksum_driver)) {
                        ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -3467,7 +3475,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        /* Precompute checksum seed for all metadata */
        if (ext4_has_feature_csum_seed(sb))
                sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
-       else if (ext4_has_metadata_csum(sb))
+       else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
                sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
                                               sizeof(es->s_uuid));
 
@@ -3597,6 +3605,16 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                                 "The Hurd can't support 64-bit file systems");
                        goto failed_mount;
                }
+
+               /*
+                * ea_inode feature uses l_i_version field which is not
+                * available in HURD_COMPAT mode.
+                */
+               if (ext4_has_feature_ea_inode(sb)) {
+                       ext4_msg(sb, KERN_ERR,
+                                "ea_inode feature is not supported for Hurd");
+                       goto failed_mount;
+               }
        }
 
        if (IS_EXT2_SB(sb)) {
@@ -4067,6 +4085,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                goto failed_mount_wq;
        }
 
+       if (ext4_has_feature_ea_inode(sb)) {
+               sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+               if (!sbi->s_ea_inode_cache) {
+                       ext4_msg(sb, KERN_ERR,
+                                "Failed to create an s_ea_inode_cache");
+                       goto failed_mount_wq;
+               }
+       }
+
        if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
            (blocksize != PAGE_SIZE)) {
                ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4323,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        if (EXT4_SB(sb)->rsv_conversion_wq)
                destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);
 failed_mount_wq:
+       if (sbi->s_ea_inode_cache) {
+               ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+               sbi->s_ea_inode_cache = NULL;
+       }
        if (sbi->s_mb_cache) {
                ext4_xattr_destroy_cache(sbi->s_mb_cache);
                sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +778 -260
index 0484df8dadd1..d7e60358ec91 100644
@@ -108,6 +108,9 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 #define EXT4_GET_MB_CACHE(inode)       (((struct ext4_sb_info *) \
                                inode->i_sb->s_fs_info)->s_mb_cache)
 
+#define EA_INODE_CACHE(inode)  (((struct ext4_sb_info *) \
+                               inode->i_sb->s_fs_info)->s_ea_inode_cache)
+
 static int
 ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
                        struct inode *inode);
@@ -280,15 +283,44 @@ ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
        return cmp ? -ENODATA : 0;
 }
 
+static u32
+ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
+{
+       return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
+}
+
+static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
+{
+       return ((u64)ea_inode->i_ctime.tv_sec << 32) |
+              ((u32)ea_inode->i_version);
+}
+
+static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
+{
+       ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
+       ea_inode->i_version = (u32)ref_count;
+}
+
+static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
+{
+       return (u32)ea_inode->i_atime.tv_sec;
+}
+
+static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
+{
+       ea_inode->i_atime.tv_sec = hash;
+}
+
 /*
  * Read the EA value from an inode.
  */
 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 {
        unsigned long block = 0;
-       struct buffer_head *bh = NULL;
+       struct buffer_head *bh;
        int blocksize = ea_inode->i_sb->s_blocksize;
        size_t csize, copied = 0;
+       void *copy_pos = buf;
 
        while (copied < size) {
                csize = (size - copied) > blocksize ? blocksize : size - copied;
@@ -298,10 +330,10 @@ static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
                if (!bh)
                        return -EFSCORRUPTED;
 
-               memcpy(buf, bh->b_data, csize);
+               memcpy(copy_pos, bh->b_data, csize);
                brelse(bh);
 
-               buf += csize;
+               copy_pos += csize;
                block += 1;
                copied += csize;
        }
@@ -317,29 +349,24 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
        inode = ext4_iget(parent->i_sb, ea_ino);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
-               ext4_error(parent->i_sb, "error while reading EA inode %lu "
-                          "err=%d", ea_ino, err);
+               ext4_error(parent->i_sb,
+                          "error while reading EA inode %lu err=%d", ea_ino,
+                          err);
                return err;
        }
 
        if (is_bad_inode(inode)) {
-               ext4_error(parent->i_sb, "error while reading EA inode %lu "
-                          "is_bad_inode", ea_ino);
+               ext4_error(parent->i_sb,
+                          "error while reading EA inode %lu is_bad_inode",
+                          ea_ino);
                err = -EIO;
                goto error;
        }
 
-       if (EXT4_XATTR_INODE_GET_PARENT(inode) != parent->i_ino ||
-           inode->i_generation != parent->i_generation) {
-               ext4_error(parent->i_sb, "Backpointer from EA inode %lu "
-                          "to parent is invalid.", ea_ino);
-               err = -EINVAL;
-               goto error;
-       }
-
        if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
-               ext4_error(parent->i_sb, "EA inode %lu does not have "
-                          "EXT4_EA_INODE_FL flag set.\n", ea_ino);
+               ext4_error(parent->i_sb,
+                          "EA inode %lu does not have EXT4_EA_INODE_FL flag",
+                           ea_ino);
                err = -EINVAL;
                goto error;
        }
@@ -351,6 +378,20 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
        return err;
 }
 
+static int
+ext4_xattr_inode_verify_hash(struct inode *ea_inode, void *buffer, size_t size)
+{
+       u32 hash;
+
+       /* Verify stored hash matches calculated hash. */
+       hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
+       if (hash != ext4_xattr_inode_get_hash(ea_inode))
+               return -EFSCORRUPTED;
+       return 0;
+}
+
+#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
+
 /*
  * Read the value from the EA inode.
  */
@@ -358,17 +399,53 @@ static int
 ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
                     size_t size)
 {
+       struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
        struct inode *ea_inode;
-       int ret;
+       int err;
 
-       ret = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-       if (ret)
-               return ret;
+       err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+       if (err) {
+               ea_inode = NULL;
+               goto out;
+       }
 
-       ret = ext4_xattr_inode_read(ea_inode, buffer, size);
-       iput(ea_inode);
+       if (i_size_read(ea_inode) != size) {
+               ext4_warning_inode(ea_inode,
+                                  "ea_inode file size=%llu entry size=%zu",
+                                  i_size_read(ea_inode), size);
+               err = -EFSCORRUPTED;
+               goto out;
+       }
 
-       return ret;
+       err = ext4_xattr_inode_read(ea_inode, buffer, size);
+       if (err)
+               goto out;
+
+       err = ext4_xattr_inode_verify_hash(ea_inode, buffer, size);
+       /*
+        * Compatibility check for old Lustre ea_inode implementation. Old
+        * version does not have hash validation, but it has a backpointer
+        * from ea_inode to the parent inode.
+        */
+       if (err == -EFSCORRUPTED) {
+               if (EXT4_XATTR_INODE_GET_PARENT(ea_inode) != inode->i_ino ||
+                   ea_inode->i_generation != inode->i_generation) {
+                       ext4_warning_inode(ea_inode,
+                                          "EA inode hash validation failed");
+                       goto out;
+               }
+               /* Do not add ea_inode to the cache. */
+               ea_inode_cache = NULL;
+       } else if (err)
+               goto out;
+
+       if (ea_inode_cache)
+               mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
+                                     ext4_xattr_inode_get_hash(ea_inode),
+                                     ea_inode->i_ino, true /* reusable */);
+out:
+       iput(ea_inode);
+       return err;
 }
 
 static int
@@ -657,6 +734,101 @@ static void ext4_xattr_update_super_block(handle_t *handle,
        }
 }
 
+static inline size_t round_up_cluster(struct inode *inode, size_t length)
+{
+       struct super_block *sb = inode->i_sb;
+       size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
+                                   inode->i_blkbits);
+       size_t mask = ~(cluster_size - 1);
+
+       return (length + cluster_size - 1) & mask;
+}
+
+static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
+{
+       int err;
+
+       err = dquot_alloc_inode(inode);
+       if (err)
+               return err;
+       err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
+       if (err)
+               dquot_free_inode(inode);
+       return err;
+}
+
+static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
+{
+       dquot_free_space_nodirty(inode, round_up_cluster(inode, len));
+       dquot_free_inode(inode);
+}
+
+static int __ext4_xattr_set_credits(struct super_block *sb,
+                                   struct buffer_head *block_bh,
+                                   size_t value_len)
+{
+       int credits;
+       int blocks;
+
+       /*
+        * 1) Owner inode update
+        * 2) Ref count update on old xattr block
+        * 3) new xattr block
+        * 4) block bitmap update for new xattr block
+        * 5) group descriptor for new xattr block
+        */
+       credits = 5;
+
+       /* We are done if ea_inode feature is not enabled. */
+       if (!ext4_has_feature_ea_inode(sb))
+               return credits;
+
+       /* New ea_inode, inode map, block bitmap, group descriptor. */
+       credits += 4;
+
+       /* Data blocks. */
+       blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+
+       /* Indirection block or one level of extent tree. */
+       blocks += 1;
+
+       /* Block bitmap and group descriptor updates for each block. */
+       credits += blocks * 2;
+
+       /* Blocks themselves. */
+       credits += blocks;
+
+       /* Dereference ea_inode holding old xattr value.
+        * Old ea_inode, inode map, block bitmap, group descriptor.
+        */
+       credits += 4;
+
+       /* Data blocks for old ea_inode. */
+       blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+
+       /* Indirection block or one level of extent tree for old ea_inode. */
+       blocks += 1;
+
+       /* Block bitmap and group descriptor updates for each block. */
+       credits += blocks * 2;
+
+       /* Quota updates. */
+       credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
+
+       /* We may need to clone the existing xattr block in which case we need
+        * to increment ref counts for existing ea_inodes referenced by it.
+        */
+       if (block_bh) {
+               struct ext4_xattr_entry *entry = BFIRST(block_bh);
+
+               for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
+                       if (entry->e_value_inum)
+                               /* Ref count update on ea_inode. */
+                               credits += 1;
+       }
+       return credits;
+}
+
 static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
                                     int credits, struct buffer_head *bh,
                                     bool dirty, bool block_csum)
@@ -706,12 +878,140 @@ static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
        return 0;
 }
 
+static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
+                                      int ref_change)
+{
+       struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
+       struct ext4_iloc iloc;
+       s64 ref_count;
+       u32 hash;
+       int ret;
+
+       inode_lock(ea_inode);
+
+       ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
+       if (ret) {
+               iloc.bh = NULL;
+               goto out;
+       }
+
+       ref_count = ext4_xattr_inode_get_ref(ea_inode);
+       ref_count += ref_change;
+       ext4_xattr_inode_set_ref(ea_inode, ref_count);
+
+       if (ref_change > 0) {
+               WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
+                         ea_inode->i_ino, ref_count);
+
+               if (ref_count == 1) {
+                       WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
+                                 ea_inode->i_ino, ea_inode->i_nlink);
+
+                       set_nlink(ea_inode, 1);
+                       ext4_orphan_del(handle, ea_inode);
+
+                       hash = ext4_xattr_inode_get_hash(ea_inode);
+                       mb_cache_entry_create(ea_inode_cache, GFP_NOFS, hash,
+                                             ea_inode->i_ino,
+                                             true /* reusable */);
+               }
+       } else {
+               WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
+                         ea_inode->i_ino, ref_count);
+
+               if (ref_count == 0) {
+                       WARN_ONCE(ea_inode->i_nlink != 1,
+                                 "EA inode %lu i_nlink=%u",
+                                 ea_inode->i_ino, ea_inode->i_nlink);
+
+                       clear_nlink(ea_inode);
+                       ext4_orphan_add(handle, ea_inode);
+
+                       hash = ext4_xattr_inode_get_hash(ea_inode);
+                       mb_cache_entry_delete(ea_inode_cache, hash,
+                                             ea_inode->i_ino);
+               }
+       }
+
+       ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
+       iloc.bh = NULL;
+       if (ret)
+               ext4_warning_inode(ea_inode,
+                                  "ext4_mark_iloc_dirty() failed ret=%d", ret);
+out:
+       brelse(iloc.bh);
+       inode_unlock(ea_inode);
+       return ret;
+}
+
+static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
+{
+       return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
+}
+
+static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
+{
+       return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
+}
+
+static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
+                                       struct ext4_xattr_entry *first)
+{
+       struct inode *ea_inode;
+       struct ext4_xattr_entry *entry;
+       struct ext4_xattr_entry *failed_entry;
+       unsigned int ea_ino;
+       int err, saved_err;
+
+       for (entry = first; !IS_LAST_ENTRY(entry);
+            entry = EXT4_XATTR_NEXT(entry)) {
+               if (!entry->e_value_inum)
+                       continue;
+               ea_ino = le32_to_cpu(entry->e_value_inum);
+               err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+               if (err)
+                       goto cleanup;
+               err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+               if (err) {
+                       ext4_warning_inode(ea_inode, "inc ref error %d", err);
+                       iput(ea_inode);
+                       goto cleanup;
+               }
+               iput(ea_inode);
+       }
+       return 0;
+
+cleanup:
+       saved_err = err;
+       failed_entry = entry;
+
+       for (entry = first; entry != failed_entry;
+            entry = EXT4_XATTR_NEXT(entry)) {
+               if (!entry->e_value_inum)
+                       continue;
+               ea_ino = le32_to_cpu(entry->e_value_inum);
+               err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+               if (err) {
+                       ext4_warning(parent->i_sb,
+                                    "cleanup ea_ino %u iget error %d", ea_ino,
+                                    err);
+                       continue;
+               }
+               err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+               if (err)
+                       ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
+                                          err);
+               iput(ea_inode);
+       }
+       return saved_err;
+}
+
 static void
-ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
-                           struct buffer_head *bh,
-                           struct ext4_xattr_entry *first, bool block_csum,
-                           struct ext4_xattr_inode_array **ea_inode_array,
-                           int extra_credits)
+ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
+                            struct buffer_head *bh,
+                            struct ext4_xattr_entry *first, bool block_csum,
+                            struct ext4_xattr_inode_array **ea_inode_array,
+                            int extra_credits, bool skip_quota)
 {
        struct inode *ea_inode;
        struct ext4_xattr_entry *entry;
@@ -748,10 +1048,16 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
                        continue;
                }
 
-               inode_lock(ea_inode);
-               clear_nlink(ea_inode);
-               ext4_orphan_add(handle, ea_inode);
-               inode_unlock(ea_inode);
+               err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+               if (err) {
+                       ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
+                                          err);
+                       continue;
+               }
+
+               if (!skip_quota)
+                       ext4_xattr_inode_free_quota(parent,
+                                             le32_to_cpu(entry->e_value_size));
 
                /*
                 * Forget about ea_inode within the same transaction that
@@ -785,7 +1091,9 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
  */
 static void
 ext4_xattr_release_block(handle_t *handle, struct inode *inode,
-                        struct buffer_head *bh)
+                        struct buffer_head *bh,
+                        struct ext4_xattr_inode_array **ea_inode_array,
+                        int extra_credits)
 {
        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
        u32 hash, ref;
@@ -808,6 +1116,14 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
                mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
                get_bh(bh);
                unlock_buffer(bh);
+
+               if (ext4_has_feature_ea_inode(inode->i_sb))
+                       ext4_xattr_inode_dec_ref_all(handle, inode, bh,
+                                                    BFIRST(bh),
+                                                    true /* block_csum */,
+                                                    ea_inode_array,
+                                                    extra_credits,
+                                                    true /* skip_quota */);
                ext4_free_blocks(handle, inode, bh, 0, 1,
                                 EXT4_FREE_BLOCKS_METADATA |
                                 EXT4_FREE_BLOCKS_FORGET);
@@ -879,8 +1195,8 @@ static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
 {
        struct buffer_head *bh = NULL;
        unsigned long block = 0;
-       unsigned blocksize = ea_inode->i_sb->s_blocksize;
-       unsigned max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
+       int blocksize = ea_inode->i_sb->s_blocksize;
+       int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
        int csize, wsize = 0;
        int ret = 0;
        int retries = 0;
@@ -948,7 +1264,7 @@ static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
  * Create an inode to store the value of a large EA.
  */
 static struct inode *ext4_xattr_inode_create(handle_t *handle,
-                                            struct inode *inode)
+                                            struct inode *inode, u32 hash)
 {
        struct inode *ea_inode = NULL;
        uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
@@ -966,67 +1282,115 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
                ea_inode->i_fop = &ext4_file_operations;
                ext4_set_aops(ea_inode);
                ext4_xattr_inode_set_class(ea_inode);
-               ea_inode->i_generation = inode->i_generation;
-               EXT4_I(ea_inode)->i_flags |= EXT4_EA_INODE_FL;
-
-               /*
-                * A back-pointer from EA inode to parent inode will be useful
-                * for e2fsck.
-                */
-               EXT4_XATTR_INODE_SET_PARENT(ea_inode, inode->i_ino);
                unlock_new_inode(ea_inode);
-               err = ext4_inode_attach_jinode(ea_inode);
+               ext4_xattr_inode_set_ref(ea_inode, 1);
+               ext4_xattr_inode_set_hash(ea_inode, hash);
+               err = ext4_mark_inode_dirty(handle, ea_inode);
+               if (!err)
+                       err = ext4_inode_attach_jinode(ea_inode);
                if (err) {
                        iput(ea_inode);
                        return ERR_PTR(err);
                }
+
+               /*
+                * Xattr inodes are shared therefore quota charging is performed
+                * at a higher level.
+                */
+               dquot_free_inode(ea_inode);
+               dquot_drop(ea_inode);
+               inode_lock(ea_inode);
+               ea_inode->i_flags |= S_NOQUOTA;
+               inode_unlock(ea_inode);
        }
 
        return ea_inode;
 }
 
-/*
- * Unlink the inode storing the value of the EA.
- */
-int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino)
+static struct inode *
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+                           size_t value_len, u32 hash)
 {
-       struct inode *ea_inode = NULL;
-       int err;
+       struct inode *ea_inode;
+       struct mb_cache_entry *ce;
+       struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+       void *ea_data;
 
-       err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-       if (err)
-               return err;
+       ce = mb_cache_entry_find_first(ea_inode_cache, hash);
+       if (!ce)
+               return NULL;
 
-       clear_nlink(ea_inode);
-       iput(ea_inode);
+       ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
+       if (!ea_data) {
+               mb_cache_entry_put(ea_inode_cache, ce);
+               return NULL;
+       }
 
-       return 0;
+       while (ce) {
+               ea_inode = ext4_iget(inode->i_sb, ce->e_value);
+               if (!IS_ERR(ea_inode) &&
+                   !is_bad_inode(ea_inode) &&
+                   (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
+                   i_size_read(ea_inode) == value_len &&
+                   !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
+                   !ext4_xattr_inode_verify_hash(ea_inode, ea_data,
+                                                 value_len) &&
+                   !memcmp(value, ea_data, value_len)) {
+                       mb_cache_entry_touch(ea_inode_cache, ce);
+                       mb_cache_entry_put(ea_inode_cache, ce);
+                       kvfree(ea_data);
+                       return ea_inode;
+               }
+
+               if (!IS_ERR(ea_inode))
+                       iput(ea_inode);
+               ce = mb_cache_entry_find_next(ea_inode_cache, ce);
+       }
+       kvfree(ea_data);
+       return NULL;
 }
 
 /*
  * Add value of the EA in an inode.
  */
-static int ext4_xattr_inode_set(handle_t *handle, struct inode *inode,
-                               unsigned long *ea_ino, const void *value,
-                               size_t value_len)
+static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
+                                         const void *value, size_t value_len,
+                                         struct inode **ret_inode)
 {
        struct inode *ea_inode;
+       u32 hash;
        int err;
 
+       hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
+       ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
+       if (ea_inode) {
+               err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+               if (err) {
+                       iput(ea_inode);
+                       return err;
+               }
+
+               *ret_inode = ea_inode;
+               return 0;
+       }
+
        /* Create an inode for the EA value */
-       ea_inode = ext4_xattr_inode_create(handle, inode);
+       ea_inode = ext4_xattr_inode_create(handle, inode, hash);
        if (IS_ERR(ea_inode))
                return PTR_ERR(ea_inode);
 
        err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
-       if (err)
-               clear_nlink(ea_inode);
-       else
-               *ea_ino = ea_inode->i_ino;
+       if (err) {
+               ext4_xattr_inode_dec_ref(handle, ea_inode);
+               iput(ea_inode);
+               return err;
+       }
 
-       iput(ea_inode);
+       mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
+                             ea_inode->i_ino, true /* reusable */);
 
-       return err;
+       *ret_inode = ea_inode;
+       return 0;
 }
 
 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
@@ -1034,9 +1398,37 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
                                handle_t *handle, struct inode *inode)
 {
        struct ext4_xattr_entry *last;
-       size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
+       struct ext4_xattr_entry *here = s->here;
+       size_t min_offs = s->end - s->base, name_len = strlen(i->name);
        int in_inode = i->in_inode;
-       int rc;
+       struct inode *old_ea_inode = NULL;
+       struct inode *new_ea_inode = NULL;
+       size_t old_size, new_size;
+       int ret;
+
+       /* Space used by old and new values. */
+       old_size = (!s->not_found && !here->e_value_inum) ?
+                       EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
+       new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
+
+       /*
+        * Optimization for the simple case when old and new values have the
+        * same padded sizes. Not applicable if external inodes are involved.
+        */
+       if (new_size && new_size == old_size) {
+               size_t offs = le16_to_cpu(here->e_value_offs);
+               void *val = s->base + offs;
+
+               here->e_value_size = cpu_to_le32(i->value_len);
+               if (i->value == EXT4_ZERO_XATTR_VALUE) {
+                       memset(val, 0, new_size);
+               } else {
+                       memcpy(val, i->value, i->value_len);
+                       /* Clear padding bytes. */
+                       memset(val + i->value_len, 0, new_size - i->value_len);
+               }
+               return 0;
+       }
 
        /* Compute min_offs and last. */
        last = s->first;
@@ -1047,122 +1439,148 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
                                min_offs = offs;
                }
        }
-       free = min_offs - ((void *)last - s->base) - sizeof(__u32);
-       if (!s->not_found) {
-               if (!in_inode &&
-                   !s->here->e_value_inum && s->here->e_value_size) {
-                       size_t size = le32_to_cpu(s->here->e_value_size);
-                       free += EXT4_XATTR_SIZE(size);
-               }
-               free += EXT4_XATTR_LEN(name_len);
-       }
+
+       /* Check whether we have enough space. */
        if (i->value) {
-               size_t value_len = EXT4_XATTR_SIZE(i->value_len);
+               size_t free;
 
-               if (in_inode)
-                       value_len = 0;
+               free = min_offs - ((void *)last - s->base) - sizeof(__u32);
+               if (!s->not_found)
+                       free += EXT4_XATTR_LEN(name_len) + old_size;
 
-               if (free < EXT4_XATTR_LEN(name_len) + value_len)
-                       return -ENOSPC;
+               if (free < EXT4_XATTR_LEN(name_len) + new_size) {
+                       ret = -ENOSPC;
+                       goto out;
+               }
        }
 
-       if (i->value && s->not_found) {
-               /* Insert the new name. */
-               size_t size = EXT4_XATTR_LEN(name_len);
-               size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
-               memmove((void *)s->here + size, s->here, rest);
-               memset(s->here, 0, size);
-               s->here->e_name_index = i->name_index;
-               s->here->e_name_len = name_len;
-               memcpy(s->here->e_name, i->name, name_len);
-       } else {
-               if (!s->here->e_value_inum && s->here->e_value_size &&
-                   s->here->e_value_offs > 0) {
-                       void *first_val = s->base + min_offs;
-                       size_t offs = le16_to_cpu(s->here->e_value_offs);
-                       void *val = s->base + offs;
-                       size_t size = EXT4_XATTR_SIZE(
-                               le32_to_cpu(s->here->e_value_size));
-
-                       if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
-                               /* The old and the new value have the same
-                                  size. Just replace. */
-                               s->here->e_value_size =
-                                       cpu_to_le32(i->value_len);
-                               if (i->value == EXT4_ZERO_XATTR_VALUE) {
-                                       memset(val, 0, size);
-                               } else {
-                                       /* Clear pad bytes first. */
-                                       memset(val + size - EXT4_XATTR_PAD, 0,
-                                              EXT4_XATTR_PAD);
-                                       memcpy(val, i->value, i->value_len);
-                               }
-                               return 0;
-                       }
+       /*
+        * Getting access to old and new ea inodes is subject to failures.
+        * Finish that work before doing any modifications to the xattr data.
+        */
+       if (!s->not_found && here->e_value_inum) {
+               ret = ext4_xattr_inode_iget(inode,
+                                           le32_to_cpu(here->e_value_inum),
+                                           &old_ea_inode);
+               if (ret) {
+                       old_ea_inode = NULL;
+                       goto out;
+               }
+       }
+       if (i->value && in_inode) {
+               WARN_ON_ONCE(!i->value_len);
 
-                       /* Remove the old value. */
-                       memmove(first_val + size, first_val, val - first_val);
-                       memset(first_val, 0, size);
-                       s->here->e_value_size = 0;
-                       s->here->e_value_offs = 0;
-                       min_offs += size;
-
-                       /* Adjust all value offsets. */
-                       last = s->first;
-                       while (!IS_LAST_ENTRY(last)) {
-                               size_t o = le16_to_cpu(last->e_value_offs);
-                               if (!last->e_value_inum &&
-                                   last->e_value_size && o < offs)
-                                       last->e_value_offs =
-                                               cpu_to_le16(o + size);
-                               last = EXT4_XATTR_NEXT(last);
-                       }
+               ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
+               if (ret)
+                       goto out;
+
+               ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
+                                                    i->value_len,
+                                                    &new_ea_inode);
+               if (ret) {
+                       new_ea_inode = NULL;
+                       ext4_xattr_inode_free_quota(inode, i->value_len);
+                       goto out;
                }
-               if (s->here->e_value_inum) {
-                       ext4_xattr_inode_unlink(inode,
-                                           le32_to_cpu(s->here->e_value_inum));
-                       s->here->e_value_inum = 0;
+       }
+
+       if (old_ea_inode) {
+               /* We are ready to release ref count on the old_ea_inode. */
+               ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
+               if (ret) {
+                       /* Release newly required ref count on new_ea_inode. */
+                       if (new_ea_inode) {
+                               int err;
+
+                               err = ext4_xattr_inode_dec_ref(handle,
+                                                              new_ea_inode);
+                               if (err)
+                                       ext4_warning_inode(new_ea_inode,
+                                                 "dec ref new_ea_inode err=%d",
+                                                 err);
+                               ext4_xattr_inode_free_quota(inode,
+                                                           i->value_len);
+                       }
+                       goto out;
                }
-               if (!i->value) {
-                       /* Remove the old name. */
-                       size_t size = EXT4_XATTR_LEN(name_len);
-                       last = ENTRY((void *)last - size);
-                       memmove(s->here, (void *)s->here + size,
-                               (void *)last - (void *)s->here + sizeof(__u32));
-                       memset(last, 0, size);
+
+               ext4_xattr_inode_free_quota(inode,
+                                           le32_to_cpu(here->e_value_size));
+       }
+
+       /* No failures allowed past this point. */
+
+       if (!s->not_found && here->e_value_offs) {
+               /* Remove the old value. */
+               void *first_val = s->base + min_offs;
+               size_t offs = le16_to_cpu(here->e_value_offs);
+               void *val = s->base + offs;
+
+               memmove(first_val + old_size, first_val, val - first_val);
+               memset(first_val, 0, old_size);
+               min_offs += old_size;
+
+               /* Adjust all value offsets. */
+               last = s->first;
+               while (!IS_LAST_ENTRY(last)) {
+                       size_t o = le16_to_cpu(last->e_value_offs);
+
+                       if (!last->e_value_inum &&
+                           last->e_value_size && o < offs)
+                               last->e_value_offs = cpu_to_le16(o + old_size);
+                       last = EXT4_XATTR_NEXT(last);
                }
        }
 
+       if (!i->value) {
+               /* Remove old name. */
+               size_t size = EXT4_XATTR_LEN(name_len);
+
+               last = ENTRY((void *)last - size);
+               memmove(here, (void *)here + size,
+                       (void *)last - (void *)here + sizeof(__u32));
+               memset(last, 0, size);
+       } else if (s->not_found) {
+               /* Insert new name. */
+               size_t size = EXT4_XATTR_LEN(name_len);
+               size_t rest = (void *)last - (void *)here + sizeof(__u32);
+
+               memmove((void *)here + size, here, rest);
+               memset(here, 0, size);
+               here->e_name_index = i->name_index;
+               here->e_name_len = name_len;
+               memcpy(here->e_name, i->name, name_len);
+       } else {
+               /* This is an update, reset value info. */
+               here->e_value_inum = 0;
+               here->e_value_offs = 0;
+               here->e_value_size = 0;
+       }
+
        if (i->value) {
-               /* Insert the new value. */
+               /* Insert new value. */
                if (in_inode) {
-                       unsigned long ea_ino =
-                               le32_to_cpu(s->here->e_value_inum);
-                       rc = ext4_xattr_inode_set(handle, inode, &ea_ino,
-                                                 i->value, i->value_len);
-                       if (rc)
-                               goto out;
-                       s->here->e_value_inum = cpu_to_le32(ea_ino);
-                       s->here->e_value_offs = 0;
+                       here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
                } else if (i->value_len) {
-                       size_t size = EXT4_XATTR_SIZE(i->value_len);
-                       void *val = s->base + min_offs - size;
-                       s->here->e_value_offs = cpu_to_le16(min_offs - size);
-                       s->here->e_value_inum = 0;
+                       void *val = s->base + min_offs - new_size;
+
+                       here->e_value_offs = cpu_to_le16(min_offs - new_size);
                        if (i->value == EXT4_ZERO_XATTR_VALUE) {
-                               memset(val, 0, size);
+                               memset(val, 0, new_size);
                        } else {
-                               /* Clear the pad bytes first. */
-                               memset(val + size - EXT4_XATTR_PAD, 0,
-                                      EXT4_XATTR_PAD);
                                memcpy(val, i->value, i->value_len);
+                               /* Clear padding bytes. */
+                               memset(val + i->value_len, 0,
+                                      new_size - i->value_len);
                        }
                }
-               s->here->e_value_size = cpu_to_le32(i->value_len);
+               here->e_value_size = cpu_to_le32(i->value_len);
        }
-
+       ret = 0;
 out:
-       return rc;
+       iput(old_ea_inode);
+       iput(new_ea_inode);
+       return ret;
 }
 
 struct ext4_xattr_block_find {
@@ -1224,6 +1642,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
        struct mb_cache_entry *ce = NULL;
        int error = 0;
        struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
+       struct inode *ea_inode = NULL;
+       size_t old_ea_inode_size = 0;
 
 #define header(x) ((struct ext4_xattr_header *)(x))
 
@@ -1278,6 +1698,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                        header(s->base)->h_refcount = cpu_to_le32(1);
                        s->here = ENTRY(s->base + offset);
                        s->end = s->base + bs->bh->b_size;
+
+                       /*
+                        * If existing entry points to an xattr inode, we need
+                        * to prevent ext4_xattr_set_entry() from decrementing
+                        * ref count on it because the reference belongs to the
+                        * original block. In this case, make the entry look
+                        * like it has an empty value.
+                        */
+                       if (!s->not_found && s->here->e_value_inum) {
+                               /*
+                                * Defer quota free call for previous inode
+                                * until success is guaranteed.
+                                */
+                               old_ea_inode_size = le32_to_cpu(
+                                                       s->here->e_value_size);
+                               s->here->e_value_inum = 0;
+                               s->here->e_value_size = 0;
+                       }
                }
        } else {
                /* Allocate a buffer where we construct the new block. */
@@ -1299,6 +1737,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                goto bad_block;
        if (error)
                goto cleanup;
+
+       if (i->value && s->here->e_value_inum) {
+               unsigned int ea_ino;
+
+               /*
+                * A ref count on ea_inode has been taken as part of the call to
+                * ext4_xattr_set_entry() above. We would like to drop this
+                * extra ref but we have to wait until the xattr block is
+                * initialized and has its own ref count on the ea_inode.
+                */
+               ea_ino = le32_to_cpu(s->here->e_value_inum);
+               error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+               if (error) {
+                       ea_inode = NULL;
+                       goto cleanup;
+               }
+       }
+
        if (!IS_LAST_ENTRY(s->first))
                ext4_xattr_rehash(header(s->base), s->here);
 
@@ -1409,6 +1865,22 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                                                 EXT4_FREE_BLOCKS_METADATA);
                                goto cleanup;
                        }
+                       error = ext4_xattr_inode_inc_ref_all(handle, inode,
+                                                     ENTRY(header(s->base)+1));
+                       if (error)
+                               goto getblk_failed;
+                       if (ea_inode) {
+                               /* Drop the extra ref on ea_inode. */
+                               error = ext4_xattr_inode_dec_ref(handle,
+                                                                ea_inode);
+                               if (error)
+                                       ext4_warning_inode(ea_inode,
+                                                          "dec ref error=%d",
+                                                          error);
+                               iput(ea_inode);
+                               ea_inode = NULL;
+                       }
+
                        lock_buffer(new_bh);
                        error = ext4_journal_get_create_access(handle, new_bh);
                        if (error) {
@@ -1428,15 +1900,38 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                }
        }
 
+       if (old_ea_inode_size)
+               ext4_xattr_inode_free_quota(inode, old_ea_inode_size);
+
        /* Update the inode. */
        EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 
        /* Drop the previous xattr block. */
-       if (bs->bh && bs->bh != new_bh)
-               ext4_xattr_release_block(handle, inode, bs->bh);
+       if (bs->bh && bs->bh != new_bh) {
+               struct ext4_xattr_inode_array *ea_inode_array = NULL;
+
+               ext4_xattr_release_block(handle, inode, bs->bh,
+                                        &ea_inode_array,
+                                        0 /* extra_credits */);
+               ext4_xattr_inode_array_free(ea_inode_array);
+       }
        error = 0;
 
 cleanup:
+       if (ea_inode) {
+               int error2;
+
+               error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+               if (error2)
+                       ext4_warning_inode(ea_inode, "dec ref error=%d",
+                                          error2);
+
+               /* If there was an error, revert the quota charge. */
+               if (error)
+                       ext4_xattr_inode_free_quota(inode,
+                                                   i_size_read(ea_inode));
+               iput(ea_inode);
+       }
        if (ce)
                mb_cache_entry_put(ext4_mb_cache, ce);
        brelse(new_bh);
@@ -1561,6 +2056,22 @@ static int ext4_xattr_value_same(struct ext4_xattr_search *s,
        return !memcmp(value, i->value, i->value_len);
 }
 
+static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
+{
+       struct buffer_head *bh;
+       int error;
+
+       if (!EXT4_I(inode)->i_file_acl)
+               return NULL;
+       bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+       if (!bh)
+               return ERR_PTR(-EIO);
+       error = ext4_xattr_check_block(inode, bh);
+       if (error)
+               return ERR_PTR(error);
+       return bh;
+}
+
 /*
  * ext4_xattr_set_handle()
  *
@@ -1603,9 +2114,18 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 
        /* Check journal credits under write lock. */
        if (ext4_handle_valid(handle)) {
+               struct buffer_head *bh;
                int credits;
 
-               credits = ext4_xattr_set_credits(inode, value_len);
+               bh = ext4_xattr_get_block(inode);
+               if (IS_ERR(bh)) {
+                       error = PTR_ERR(bh);
+                       goto cleanup;
+               }
+
+               credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+               brelse(bh);
+
                if (!ext4_handle_has_enough_credits(handle, credits)) {
                        error = -ENOSPC;
                        goto cleanup;
@@ -1641,6 +2161,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
                if (flags & XATTR_CREATE)
                        goto cleanup;
        }
+
        if (!value) {
                if (!is.s.not_found)
                        error = ext4_xattr_ibody_set(handle, inode, &i, &is);
@@ -1709,34 +2230,29 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
        return error;
 }
 
-int ext4_xattr_set_credits(struct inode *inode, size_t value_len)
+int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
 {
-       struct super_block *sb = inode->i_sb;
-       int credits;
-
-       if (!EXT4_SB(sb)->s_journal)
-               return 0;
+       struct buffer_head *bh;
+       int err;
 
-       credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+       *credits = 0;
 
-       /*
-        * In case of inline data, we may push out the data to a block,
-        * so we need to reserve credits for this eventuality
-        */
-       if (ext4_has_inline_data(inode))
-               credits += ext4_writepage_trans_blocks(inode) + 1;
-
-       if (ext4_has_feature_ea_inode(sb)) {
-               int nrblocks = (value_len + sb->s_blocksize - 1) >>
-                                       sb->s_blocksize_bits;
+       if (!EXT4_SB(inode->i_sb)->s_journal)
+               return 0;
 
-               /* For new inode */
-               credits += EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + 3;
+       down_read(&EXT4_I(inode)->xattr_sem);
 
-               /* For data blocks of EA inode */
-               credits += ext4_meta_trans_blocks(inode, nrblocks, 0);
+       bh = ext4_xattr_get_block(inode);
+       if (IS_ERR(bh)) {
+               err = PTR_ERR(bh);
+       } else {
+               *credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+               brelse(bh);
+               err = 0;
        }
-       return credits;
+
+       up_read(&EXT4_I(inode)->xattr_sem);
+       return err;
 }
 
 /*
@@ -1761,7 +2277,10 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
                return error;
 
 retry:
-       credits = ext4_xattr_set_credits(inode, value_len);
+       error = ext4_xattr_set_credits(inode, value_len, &credits);
+       if (error)
+               return error;
+
        handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
        if (IS_ERR(handle)) {
                error = PTR_ERR(handle);
@@ -2067,10 +2586,10 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
        return error;
 }
 
-
 #define EIA_INCR 16 /* must be 2^n */
 #define EIA_MASK (EIA_INCR - 1)
-/* Add the large xattr @inode into @ea_inode_array for later deletion.
+
+/* Add the large xattr @inode into @ea_inode_array for deferred iput().
  * If @ea_inode_array is new or full it will be grown and the old
  * contents copied over.
  */
@@ -2115,21 +2634,19 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
  * ext4_xattr_delete_inode()
  *
  * Free extended attribute resources associated with this inode. Traverse
- * all entries and unlink any xattr inodes associated with this inode. This
- * is called immediately before an inode is freed. We have exclusive
- * access to the inode. If an orphan inode is deleted it will also delete any
- * xattr block and all xattr inodes. They are checked by ext4_xattr_inode_iget()
- * to ensure they belong to the parent inode and were not deleted already.
+ * all entries and decrement reference on any xattr inodes associated with this
+ * inode. This is called immediately before an inode is freed. We have exclusive
+ * access to the inode. If an orphan inode is deleted it will also release its
+ * references on xattr block and xattr inodes.
  */
-int
-ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-                       struct ext4_xattr_inode_array **ea_inode_array,
-                       int extra_credits)
+int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+                           struct ext4_xattr_inode_array **ea_inode_array,
+                           int extra_credits)
 {
        struct buffer_head *bh = NULL;
        struct ext4_xattr_ibody_header *header;
-       struct ext4_inode *raw_inode;
        struct ext4_iloc iloc = { .bh = NULL };
+       struct ext4_xattr_entry *entry;
        int error;
 
        error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
@@ -2141,66 +2658,71 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
                goto cleanup;
        }
 
-       if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
-               goto delete_external_ea;
+       if (ext4_has_feature_ea_inode(inode->i_sb) &&
+           ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 
-       error = ext4_get_inode_loc(inode, &iloc);
-       if (error)
-               goto cleanup;
-
-       error = ext4_journal_get_write_access(handle, iloc.bh);
-       if (error)
-               goto cleanup;
+               error = ext4_get_inode_loc(inode, &iloc);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
+                       goto cleanup;
+               }
 
-       raw_inode = ext4_raw_inode(&iloc);
-       header = IHDR(inode, raw_inode);
-       ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),
-                                   false /* block_csum */, ea_inode_array,
-                                   extra_credits);
+               error = ext4_journal_get_write_access(handle, iloc.bh);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "write access (error %d)",
+                                        error);
+                       goto cleanup;
+               }
 
-delete_external_ea:
-       if (!EXT4_I(inode)->i_file_acl) {
-               error = 0;
-               goto cleanup;
-       }
-       bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
-       if (!bh) {
-               EXT4_ERROR_INODE(inode, "block %llu read error",
-                                EXT4_I(inode)->i_file_acl);
-               error = -EIO;
-               goto cleanup;
-       }
-       if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
-           BHDR(bh)->h_blocks != cpu_to_le32(1)) {
-               EXT4_ERROR_INODE(inode, "bad block %llu",
-                                EXT4_I(inode)->i_file_acl);
-               error = -EFSCORRUPTED;
-               goto cleanup;
+               header = IHDR(inode, ext4_raw_inode(&iloc));
+               if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+                       ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
+                                                    IFIRST(header),
+                                                    false /* block_csum */,
+                                                    ea_inode_array,
+                                                    extra_credits,
+                                                    false /* skip_quota */);
        }
 
-       if (ext4_has_feature_ea_inode(inode->i_sb)) {
-               error = ext4_journal_get_write_access(handle, bh);
-               if (error) {
-                       EXT4_ERROR_INODE(inode, "write access %llu",
+       if (EXT4_I(inode)->i_file_acl) {
+               bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+               if (!bh) {
+                       EXT4_ERROR_INODE(inode, "block %llu read error",
                                         EXT4_I(inode)->i_file_acl);
+                       error = -EIO;
+                       goto cleanup;
+               }
+               error = ext4_xattr_check_block(inode, bh);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
+                                        EXT4_I(inode)->i_file_acl, error);
                        goto cleanup;
                }
-               ext4_xattr_inode_remove_all(handle, inode, bh,
-                                           BFIRST(bh),
-                                           true /* block_csum */,
-                                           ea_inode_array,
-                                           extra_credits);
-       }
 
-       ext4_xattr_release_block(handle, inode, bh);
-       /* Update i_file_acl within the same transaction that releases block. */
-       EXT4_I(inode)->i_file_acl = 0;
-       error = ext4_mark_inode_dirty(handle, inode);
-       if (error) {
-               EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
-                                error);
-               goto cleanup;
+               if (ext4_has_feature_ea_inode(inode->i_sb)) {
+                       for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+                            entry = EXT4_XATTR_NEXT(entry))
+                               if (entry->e_value_inum)
+                                       ext4_xattr_inode_free_quota(inode,
+                                             le32_to_cpu(entry->e_value_size));
+
+               }
+
+               ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
+                                        extra_credits);
+               /*
+                * Update i_file_acl value in the same transaction that releases
+                * block.
+                */
+               EXT4_I(inode)->i_file_acl = 0;
+               error = ext4_mark_inode_dirty(handle, inode);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+                                        error);
+                       goto cleanup;
+               }
        }
+       error = 0;
 cleanup:
        brelse(iloc.bh);
        brelse(bh);
@@ -2209,17 +2731,13 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 
 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
 {
-       struct inode    *ea_inode;
-       int             idx = 0;
+       int idx;
 
        if (ea_inode_array == NULL)
                return;
 
-       for (; idx < ea_inode_array->count; ++idx) {
-               ea_inode = ea_inode_array->inodes[idx];
-               clear_nlink(ea_inode);
-               iput(ea_inode);
-       }
+       for (idx = 0; idx < ea_inode_array->count; ++idx)
+               iput(ea_inode_array->inodes[idx]);
        kfree(ea_inode_array);
 }
 
fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -69,19 +69,6 @@ struct ext4_xattr_entry {
                EXT4_I(inode)->i_extra_isize))
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
-/*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
 /*
  * The minimum size of EA value when you start storing it in an external inode
  * size of block - size of header - size of 1 entry - 4 null bytes
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+                                 int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
                                   struct ext4_xattr_inode_array **array,
                                   int extra_credits);
fs/mbcache.c +5 -5
index 45a8d52dc991..d818fd236787 100644
@@ -13,10 +13,11 @@
  * mb_cache_entry_delete()).
  *
  * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
  *
  * We provide functions for creation and removal of entries, search by key,
  * and a special "delete entry with given key-value pair" operation. Fixed
--

2.13.1.518.g3df882009-goog

#57 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

Quoted 9 lines · Tahsin Erdogan

Thanks Andreas for the feedback. Please see my responses below:

Quoted 5 lines

It would be preferable to allow a mount option like "no_mbcache" to disable the use of shared xattrs. In the Lustre case at least, there will never be shared large xattrs, and we've had a bunch of performance issues with mbcache due to lock contention among many server threads doing concurrent lookups and inserting many thousands of unique entries into the cache.

Quoted 4 lines

I have put nombcache mount option in a separate patch ("[PATCH 32/32]
ext4: add nombcache mount option"). I have named it nombcache instead of no_mbcache to be consistent with other no* options. Let me know if you prefer no_mbcache as the option name.

Tashin, we are already using the "no_mbcache" option name, so would prefer to keep that working. It would be OK to accept both option names to mean the same thing, and only document the "nombcache" option.

Quoted 14 lines
Quoted 4 lines

This should follow the existing convention of always using s_csum_seed to seed the checksum, and change ext4_fill_super() to initialize s_csum_seed to ~0 if ext4_has_metadata_csum() is false, or always use the same value regardless of whether ext4_has_metadata_csum() is set or not.

Done.

Quoted 4 lines

If it really necessary to have more than 2^32 references on a single shared inode then it would be better to avoid the re-use of i_mtime, which breaks the backref for unshared xattrs, and using i_size isn't enough of a guarantee that this is the correct parent inode in case of on-disk corruption.

I have now moved the lower 32bits of ref count from i_mtime to l_i_version.

Quoted 8 lines
Quoted 5 lines

Should this be contingent on ext4_has_metadata_csum() feature being enabled, or alternately check if EXT4_XATTR_INODE_GET_PARENT() and i_generation match before returning an error. This will allow a smooth transition from existing filesystems that do not store the hash, but have only a single-use xattr inode with a parent backref.

I updated hash validation to fallback to parent backref check for backward compatibility.

Great, thanks.

Quoted 8 lines
Quoted 4 lines

Review

Quoted 2 lines
(quoted diff) +2 -0
+     /* Indirection block. */
+     blocks += 1;

Strictly speaking, this is only needed "if (blocks > EXT4_NDIR_BLOCKS)".

Ack. I didn't think it was worth going through exact calculation in this case, let me know if you see value in doing that.
I also updated the comment to mention extents.

This one credit isn't a huge deal. In general, the number of credits reserved can affect performance if they get too large, especially if there are a large number of threads active, since this will cause premature journal flushing and reduce the number of shared blocks written in the same transaction.

Quoted 25 lines
Quoted 10 lines

fs/ext4/xattr.c static void ext4_xattr_update_super_block(handle_t *handle, · line 820

Quoted 3 lines
fs/ext4/xattr.c +3 -0
+     /* We may need to clone the existing xattr block in which case we need
+      * to increment ref counts for existing ea_inodes referenced by it.
+      */

Just to clarify here, in the case of cloning an existing xattr block, are the refcounts being _incremented_ or _decremented_ on the existing ea_inodes? I'm trying to figure out if we really need to have credits for both old and new xattr inodes, as well as these additional credits. Since this is reserving about 110 blocks for every setxattr, this can add significant pressure on the journal if there are lots of threads creating files and/or setting xattrs.

Cloning causes incrementing xattr inode references.

Quoted 11 lines

fs/ext4/xattr.c static struct inode *ext4_xattr_inode_create(handle_t *handle, · line 1362

Quoted 8 lines
fs/ext4/xattr.c +2 -0
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+                         size_t value_len, u32 hash)

{

fs/ext4/xattr.c +4 -0
+     struct inode *ea_inode;
+     struct mb_cache_entry *ce;
+     struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+     void *ea_data = NULL;
     int err;

This function should just return NULL if ea_inode_cache is NULL (e.g. in the case of "no_mbcache" mount option).

Quoted 7 lines

Done in later patch ("[PATCH 32/32] ext4: add nombcache mount option")

Quoted 3 lines

Should skip mb_cache if EA_INODE_CACHE(inode) is NULL, or have a wrapper like ext4_xattr_inode_cache_insert() to match ext4_xattr_inode_cache_find() that does the same.

Added skip in patch ("[PATCH 32/32] ext4: add nombcache mount option")

Thanks, I'm just going to go through those patches.

Cheers, Andreas

Quoted 1,682 lines · Tahsin Erdogan
Quoted 1,681 lines

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---
v5:
- made ext4_meta_trans_blocks() static again since there are no remaining users outside of inode.c
- initialize sbi->s_csum_seed when ea_inode feature is enabled
- use l_i_version to hold lower 32 bits of the xattr ref count. This avoids clashes with old implementations which use i_mtime. Since l_i_version is not available in HURD_COMPAT mode, fail mount request when both ea_inode feature and HURD_COMPAT are set.
- when hash validation fails, fall back to old implementation which has a backref to parent.
- fixed checkpatch.pl warning about using unsigned alone

v4:
- eliminated xattr entry in the xattr inode to avoid complexity and recursion in xattr update path. Now the ref count and hash are stored in i_[c/m/a]time.tv_sec fields.
- some clean up in ext4_xattr_set_entry() to reduce code duplication and complexity

v3:
- use s_csum_seed for hash calculations when available
- return error on stored vs calculated hash mismatch

v2:
- make dependency on crc32c dynamic
- update ext4_has_metadata_csum() and ext4_has_group_desc_csum() so that they do not misinterpret existence of EXT4_SB(sb)->s_chksum_driver

fs/ext4/acl.c   |    5 +-
fs/ext4/ext4.h  |   23 +-
fs/ext4/inode.c |   13 +-
fs/ext4/super.c |   37 +-
fs/ext4/xattr.c | 1038 +++++++++++++++++++++++++++++++++++++++++--------------
fs/ext4/xattr.h |   17 +-
fs/mbcache.c    |    9 +-
7 files changed, 848 insertions(+), 294 deletions(-)
fs/ext4/acl.c +0 -0
index 74f7ac539e00..8db03e5c78bc 100644
@@ -238,7 +238,10 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
       if (error)
               return error;

retry:

fs/ext4/acl.c +4 -1
-       credits = ext4_xattr_set_credits(inode, acl_size);
+       error = ext4_xattr_set_credits(inode, acl_size, &credits);
+       if (error)
+               return error;
+
       handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
       if (IS_ERR(handle))
               return PTR_ERR(handle);
fs/ext4/ext4.h +14 -9
index d79d8d7bee88..59e9488c4876 100644
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
       long s_es_nr_inode;
       struct ext4_es_stats s_es_stats;
       struct mb_cache *s_mb_cache;
+       struct mb_cache *s_ea_inode_cache;
       spinlock_t s_es_lock ____cacheline_aligned_in_smp;
 
       /* Ratelimit ext4 messages. */
@@ -2099,7 +2100,11 @@ static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
       return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
 }
 
-#define ext4_is_quota_file(inode) IS_NOQUOTA(inode)
+static inline bool ext4_is_quota_file(struct inode *inode)
+{
+       return IS_NOQUOTA(inode) &&
+              !(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL);
+}
 
 /*
 * This structure is stuffed into the struct file's private_data field
@@ -2482,7 +2487,6 @@ extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
 extern void ext4_set_inode_flags(struct inode *);
 extern int ext4_alloc_da_blocks(struct inode *inode);
 extern void ext4_set_aops(struct inode *inode);
-extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int chunk);
 extern int ext4_writepage_trans_blocks(struct inode *);
 extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
 extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
@@ -2709,19 +2713,20 @@ extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
 extern int ext4_register_li_request(struct super_block *sb,
                                   ext4_group_t first_not_zeroed);
 
-static inline int ext4_has_group_desc_csum(struct super_block *sb)
-{
-       return ext4_has_feature_gdt_csum(sb) ||
-              EXT4_SB(sb)->s_chksum_driver != NULL;
-}
-
 static inline int ext4_has_metadata_csum(struct super_block *sb)
 {
       WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
                    !EXT4_SB(sb)->s_chksum_driver);
 
-       return (EXT4_SB(sb)->s_chksum_driver != NULL);
+       return ext4_has_feature_metadata_csum(sb) &&
+              (EXT4_SB(sb)->s_chksum_driver != NULL);
 }
+
+static inline int ext4_has_group_desc_csum(struct super_block *sb)
+{
+       return ext4_has_feature_gdt_csum(sb) || ext4_has_metadata_csum(sb);
+}
+
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
       return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
fs/ext4/inode.c +11 -2
index cd007f9757d1..ea95bd9eab81 100644
@@ -139,6 +139,8 @@ static void ext4_invalidatepage(struct page *page, unsigned int offset,
                               unsigned int length);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+                                 int pextents);
 
 /*
 * Test whether an inode is a fast symlink.
@@ -4843,8 +4845,15 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
       }
       brelse(iloc.bh);
       ext4_set_inode_flags(inode);
-       if (ei->i_flags & EXT4_EA_INODE_FL)
+
+       if (ei->i_flags & EXT4_EA_INODE_FL) {
               ext4_xattr_inode_set_class(inode);
+
+               inode_lock(inode);
+               inode->i_flags |= S_NOQUOTA;
+               inode_unlock(inode);
+       }
+
       unlock_new_inode(inode);
       return inode;
 
@@ -5503,7 +5512,7 @@ static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
 *
 * Also account for superblock, inode, quota and xattr blocks
 */
-int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
                                 int pextents)
 {
       ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
fs/ext4/super.c +4 -0
index b02a23ec92ca..2bfacd737bb6 100644
@@ -927,6 +927,10 @@ static void ext4_put_super(struct super_block *sb)
               invalidate_bdev(sbi->journal_bdev);
               ext4_blkdev_remove(sbi);
       }
+       if (sbi->s_ea_inode_cache) {
+               ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+               sbi->s_ea_inode_cache = NULL;
+       }
       if (sbi->s_mb_cache) {
               ext4_xattr_destroy_cache(sbi->s_mb_cache);
               sbi->s_mb_cache = NULL;
@@ -1178,7 +1182,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
       if (res)
               return res;

retry:

fs/ext4/super.c +26 -3
-       credits = ext4_xattr_set_credits(inode, len);
+       res = ext4_xattr_set_credits(inode, len, &credits);
+       if (res)
+               return res;
+
       handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
       if (IS_ERR(handle))
               return PTR_ERR(handle);
@@ -3445,7 +3452,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
       }
 
       /* Load the checksum driver */
-       if (ext4_has_feature_metadata_csum(sb)) {
+       if (ext4_has_feature_metadata_csum(sb) ||
+           ext4_has_feature_ea_inode(sb)) {
               sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
               if (IS_ERR(sbi->s_chksum_driver)) {
                       ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
@@ -3467,7 +3475,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
       /* Precompute checksum seed for all metadata */
       if (ext4_has_feature_csum_seed(sb))
               sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
-       else if (ext4_has_metadata_csum(sb))
+       else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
               sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
                                              sizeof(es->s_uuid));
 
@@ -3597,6 +3605,16 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                                "The Hurd can't support 64-bit file systems");
                       goto failed_mount;
               }
+
+               /*
+                * ea_inode feature uses l_i_version field which is not
+                * available in HURD_COMPAT mode.
+                */
+               if (ext4_has_feature_ea_inode(sb)) {
+                       ext4_msg(sb, KERN_ERR,
+                                "ea_inode feature is not supported for Hurd");
+                       goto failed_mount;
+               }
       }
 
       if (IS_EXT2_SB(sb)) {
@@ -4067,6 +4085,15 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
               goto failed_mount_wq;
       }
 
+       if (ext4_has_feature_ea_inode(sb)) {
+               sbi->s_ea_inode_cache = ext4_xattr_create_cache();
+               if (!sbi->s_ea_inode_cache) {
+                       ext4_msg(sb, KERN_ERR,
+                                "Failed to create an s_ea_inode_cache");
+                       goto failed_mount_wq;
+               }
+       }
+
       if ((DUMMY_ENCRYPTION_ENABLED(sbi) || ext4_has_feature_encrypt(sb)) &&
           (blocksize != PAGE_SIZE)) {
               ext4_msg(sb, KERN_ERR,
@@ -4296,6 +4323,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
       if (EXT4_SB(sb)->rsv_conversion_wq)
               destroy_workqueue(EXT4_SB(sb)->rsv_conversion_wq);

failed_mount_wq:

fs/ext4/super.c +4 -0
+       if (sbi->s_ea_inode_cache) {
+               ext4_xattr_destroy_cache(sbi->s_ea_inode_cache);
+               sbi->s_ea_inode_cache = NULL;
+       }
       if (sbi->s_mb_cache) {
               ext4_xattr_destroy_cache(sbi->s_mb_cache);
               sbi->s_mb_cache = NULL;
fs/ext4/xattr.c +3 -0
index 0484df8dadd1..d7e60358ec91 100644
@@ -108,6 +108,9 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 #define EXT4_GET_MB_CACHE(inode)       (((struct ext4_sb_info *) \
                               inode->i_sb->s_fs_info)->s_mb_cache)
 
+#define EA_INODE_CACHE(inode)  (((struct ext4_sb_info *) \
+                               inode->i_sb->s_fs_info)->s_ea_inode_cache)
+

static int
ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,

                       struct inode *inode);
fs/ext4/xattr.c +98 -24
@@ -280,15 +283,44 @@ ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
       return cmp ? -ENODATA : 0;
 }
 
+static u32
+ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size)
+{
+       return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size);
+}
+
+static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode)
+{
+       return ((u64)ea_inode->i_ctime.tv_sec << 32) |
+              ((u32)ea_inode->i_version);
+}
+
+static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count)
+{
+       ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32);
+       ea_inode->i_version = (u32)ref_count;
+}
+
+static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode)
+{
+       return (u32)ea_inode->i_atime.tv_sec;
+}
+
+static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash)
+{
+       ea_inode->i_atime.tv_sec = hash;
+}
+
 /*
 * Read the EA value from an inode.
 */
 static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
 {
       unsigned long block = 0;
-       struct buffer_head *bh = NULL;
+       struct buffer_head *bh;
       int blocksize = ea_inode->i_sb->s_blocksize;
       size_t csize, copied = 0;
+       void *copy_pos = buf;
 
       while (copied < size) {
               csize = (size - copied) > blocksize ? blocksize : size - copied;
@@ -298,10 +330,10 @@ static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size)
               if (!bh)
                       return -EFSCORRUPTED;
 
-               memcpy(buf, bh->b_data, csize);
+               memcpy(copy_pos, bh->b_data, csize);
               brelse(bh);
 
-               buf += csize;
+               copy_pos += csize;
               block += 1;
               copied += csize;
       }
@@ -317,29 +349,24 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
       inode = ext4_iget(parent->i_sb, ea_ino);
       if (IS_ERR(inode)) {
               err = PTR_ERR(inode);
-               ext4_error(parent->i_sb, "error while reading EA inode %lu "
-                          "err=%d", ea_ino, err);
+               ext4_error(parent->i_sb,
+                          "error while reading EA inode %lu err=%d", ea_ino,
+                          err);
               return err;
       }
 
       if (is_bad_inode(inode)) {
-               ext4_error(parent->i_sb, "error while reading EA inode %lu "
-                          "is_bad_inode", ea_ino);
+               ext4_error(parent->i_sb,
+                          "error while reading EA inode %lu is_bad_inode",
+                          ea_ino);
               err = -EIO;
               goto error;
       }
 
-       if (EXT4_XATTR_INODE_GET_PARENT(inode) != parent->i_ino ||
-           inode->i_generation != parent->i_generation) {
-               ext4_error(parent->i_sb, "Backpointer from EA inode %lu "
-                          "to parent is invalid.", ea_ino);
-               err = -EINVAL;
-               goto error;
-       }
-
       if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) {
-               ext4_error(parent->i_sb, "EA inode %lu does not have "
-                          "EXT4_EA_INODE_FL flag set.\n", ea_ino);
+               ext4_error(parent->i_sb,
+                          "EA inode %lu does not have EXT4_EA_INODE_FL flag",
+                           ea_ino);
               err = -EINVAL;
               goto error;
       }
@@ -351,6 +378,20 @@ static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino,
       return err;
 }
 
+static int
+ext4_xattr_inode_verify_hash(struct inode *ea_inode, void *buffer, size_t size)
+{
+       u32 hash;
+
+       /* Verify stored hash matches calculated hash. */
+       hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size);
+       if (hash != ext4_xattr_inode_get_hash(ea_inode))
+               return -EFSCORRUPTED;
+       return 0;
+}
+
+#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec)
+
 /*
 * Read the value from the EA inode.
 */
@@ -358,17 +399,53 @@ static int
 ext4_xattr_inode_get(struct inode *inode, unsigned long ea_ino, void *buffer,
                    size_t size)
 {
+       struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
       struct inode *ea_inode;
-       int ret;
+       int err;
 
-       ret = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-       if (ret)
-               return ret;
+       err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+       if (err) {
+               ea_inode = NULL;
+               goto out;
+       }
 
-       ret = ext4_xattr_inode_read(ea_inode, buffer, size);
-       iput(ea_inode);
+       if (i_size_read(ea_inode) != size) {
+               ext4_warning_inode(ea_inode,
+                                  "ea_inode file size=%llu entry size=%zu",
+                                  i_size_read(ea_inode), size);
+               err = -EFSCORRUPTED;
+               goto out;
+       }
 
-       return ret;
+       err = ext4_xattr_inode_read(ea_inode, buffer, size);
+       if (err)
+               goto out;
+
+       err = ext4_xattr_inode_verify_hash(ea_inode, buffer, size);
+       /*
+        * Compatibility check for old Lustre ea_inode implementation. Old
+        * version does not have hash validation, but it has a backpointer
+        * from ea_inode to the parent inode.
+        */
+       if (err == -EFSCORRUPTED) {
+               if (EXT4_XATTR_INODE_GET_PARENT(ea_inode) != inode->i_ino ||
+                   ea_inode->i_generation != inode->i_generation) {
+                       ext4_warning_inode(ea_inode,
+                                          "EA inode hash validation failed");
+                       goto out;
+               }
+               /* Do not add ea_inode to the cache. */
+               ea_inode_cache = NULL;
+       } else if (err)
+               goto out;
+
+       if (ea_inode_cache)
+               mb_cache_entry_create(ea_inode_cache, GFP_NOFS,
+                                     ext4_xattr_inode_get_hash(ea_inode),
+                                     ea_inode->i_ino, true /* reusable */);
+out:
+       iput(ea_inode);
+       return err;
 }
 

static int

fs/ext4/xattr.c +223 -0
@@ -657,6 +734,101 @@ static void ext4_xattr_update_super_block(handle_t *handle,
       }
 }
 
+static inline size_t round_up_cluster(struct inode *inode, size_t length)
+{
+       struct super_block *sb = inode->i_sb;
+       size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits +
+                                   inode->i_blkbits);
+       size_t mask = ~(cluster_size - 1);
+
+       return (length + cluster_size - 1) & mask;
+}
+
+static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len)
+{
+       int err;
+
+       err = dquot_alloc_inode(inode);
+       if (err)
+               return err;
+       err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len));
+       if (err)
+               dquot_free_inode(inode);
+       return err;
+}
+
+static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
+{
+       dquot_free_space_nodirty(inode, round_up_cluster(inode, len));
+       dquot_free_inode(inode);
+}
+
+static int __ext4_xattr_set_credits(struct super_block *sb,
+                                   struct buffer_head *block_bh,
+                                   size_t value_len)
+{
+       int credits;
+       int blocks;
+
+       /*
+        * 1) Owner inode update
+        * 2) Ref count update on old xattr block
+        * 3) new xattr block
+        * 4) block bitmap update for new xattr block
+        * 5) group descriptor for new xattr block
+        */
+       credits = 5;
+
+       /* We are done if ea_inode feature is not enabled. */
+       if (!ext4_has_feature_ea_inode(sb))
+               return credits;
+
+       /* New ea_inode, inode map, block bitmap, group descriptor. */
+       credits += 4;
+
+       /* Data blocks. */
+       blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
+
+       /* Indirection block or one level of extent tree. */
+       blocks += 1;
+
+       /* Block bitmap and group descriptor updates for each block. */
+       credits += blocks * 2;
+
+       /* Blocks themselves. */
+       credits += blocks;
+
+       /* Dereference ea_inode holding old xattr value.
+        * Old ea_inode, inode map, block bitmap, group descriptor.
+        */
+       credits += 4;
+
+       /* Data blocks for old ea_inode. */
+       blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits;
+
+       /* Indirection block or one level of extent tree for old ea_inode. */
+       blocks += 1;
+
+       /* Block bitmap and group descriptor updates for each block. */
+       credits += blocks * 2;
+
+       /* Quota updates. */
+       credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
+
+       /* We may need to clone the existing xattr block in which case we need
+        * to increment ref counts for existing ea_inodes referenced by it.
+        */
+       if (block_bh) {
+               struct ext4_xattr_entry *entry = BFIRST(block_bh);
+
+               for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry))
+                       if (entry->e_value_inum)
+                               /* Ref count update on ea_inode. */
+                               credits += 1;
+       }
+       return credits;
+}
+
 static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
                                    int credits, struct buffer_head *bh,
                                    bool dirty, bool block_csum)
@@ -706,12 +878,140 @@ static int ext4_xattr_ensure_credits(handle_t *handle, struct inode *inode,
       return 0;
 }
 
+static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
+                                      int ref_change)
+{
+       struct mb_cache *ea_inode_cache = EA_INODE_CACHE(ea_inode);
+       struct ext4_iloc iloc;
+       s64 ref_count;
+       u32 hash;
+       int ret;
+
+       inode_lock(ea_inode);
+
+       ret = ext4_reserve_inode_write(handle, ea_inode, &iloc);
+       if (ret) {
+               iloc.bh = NULL;
+               goto out;
+       }
+
+       ref_count = ext4_xattr_inode_get_ref(ea_inode);
+       ref_count += ref_change;
+       ext4_xattr_inode_set_ref(ea_inode, ref_count);
+
+       if (ref_change > 0) {
+               WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld",
+                         ea_inode->i_ino, ref_count);
+
+               if (ref_count == 1) {
+                       WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u",
+                                 ea_inode->i_ino, ea_inode->i_nlink);
+
+                       set_nlink(ea_inode, 1);
+                       ext4_orphan_del(handle, ea_inode);
+
+                       hash = ext4_xattr_inode_get_hash(ea_inode);
+                       mb_cache_entry_create(ea_inode_cache, GFP_NOFS, hash,
+                                             ea_inode->i_ino,
+                                             true /* reusable */);
+               }
+       } else {
+               WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld",
+                         ea_inode->i_ino, ref_count);
+
+               if (ref_count == 0) {
+                       WARN_ONCE(ea_inode->i_nlink != 1,
+                                 "EA inode %lu i_nlink=%u",
+                                 ea_inode->i_ino, ea_inode->i_nlink);
+
+                       clear_nlink(ea_inode);
+                       ext4_orphan_add(handle, ea_inode);
+
+                       hash = ext4_xattr_inode_get_hash(ea_inode);
+                       mb_cache_entry_delete(ea_inode_cache, hash,
+                                             ea_inode->i_ino);
+               }
+       }
+
+       ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc);
+       iloc.bh = NULL;
+       if (ret)
+               ext4_warning_inode(ea_inode,
+                                  "ext4_mark_iloc_dirty() failed ret=%d", ret);
+out:
+       brelse(iloc.bh);
+       inode_unlock(ea_inode);
+       return ret;
+}
+
+static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode)
+{
+       return ext4_xattr_inode_update_ref(handle, ea_inode, 1);
+}
+
+static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode)
+{
+       return ext4_xattr_inode_update_ref(handle, ea_inode, -1);
+}
+
+static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent,
+                                       struct ext4_xattr_entry *first)
+{
+       struct inode *ea_inode;
+       struct ext4_xattr_entry *entry;
+       struct ext4_xattr_entry *failed_entry;
+       unsigned int ea_ino;
+       int err, saved_err;
+
+       for (entry = first; !IS_LAST_ENTRY(entry);
+            entry = EXT4_XATTR_NEXT(entry)) {
+               if (!entry->e_value_inum)
+                       continue;
+               ea_ino = le32_to_cpu(entry->e_value_inum);
+               err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+               if (err)
+                       goto cleanup;
+               err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+               if (err) {
+                       ext4_warning_inode(ea_inode, "inc ref error %d", err);
+                       iput(ea_inode);
+                       goto cleanup;
+               }
+               iput(ea_inode);
+       }
+       return 0;
+
+cleanup:
+       saved_err = err;
+       failed_entry = entry;
+
+       for (entry = first; entry != failed_entry;
+            entry = EXT4_XATTR_NEXT(entry)) {
+               if (!entry->e_value_inum)
+                       continue;
+               ea_ino = le32_to_cpu(entry->e_value_inum);
+               err = ext4_xattr_inode_iget(parent, ea_ino, &ea_inode);
+               if (err) {
+                       ext4_warning(parent->i_sb,
+                                    "cleanup ea_ino %u iget error %d", ea_ino,
+                                    err);
+                       continue;
+               }
+               err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+               if (err)
+                       ext4_warning_inode(ea_inode, "cleanup dec ref error %d",
+                                          err);
+               iput(ea_inode);
+       }
+       return saved_err;
+}
+

static void

fs/ext4/xattr.c +5 -5
-ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
-                           struct buffer_head *bh,
-                           struct ext4_xattr_entry *first, bool block_csum,
-                           struct ext4_xattr_inode_array **ea_inode_array,
-                           int extra_credits)
+ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent,
+                            struct buffer_head *bh,
+                            struct ext4_xattr_entry *first, bool block_csum,
+                            struct ext4_xattr_inode_array **ea_inode_array,
+                            int extra_credits, bool skip_quota)
{
       struct inode *ea_inode;
       struct ext4_xattr_entry *entry;
fs/ext4/xattr.c +10 -4
@@ -748,10 +1048,16 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
                       continue;
               }
 
-               inode_lock(ea_inode);
-               clear_nlink(ea_inode);
-               ext4_orphan_add(handle, ea_inode);
-               inode_unlock(ea_inode);
+               err = ext4_xattr_inode_dec_ref(handle, ea_inode);
+               if (err) {
+                       ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d",
+                                          err);
+                       continue;
+               }
+
+               if (!skip_quota)
+                       ext4_xattr_inode_free_quota(parent,
+                                             le32_to_cpu(entry->e_value_size));
 
               /*
                * Forget about ea_inode within the same transaction that
@@ -785,7 +1091,9 @@ ext4_xattr_inode_remove_all(handle_t *handle, struct inode *parent,
 */

static void
ext4_xattr_release_block(handle_t *handle, struct inode *inode,

fs/ext4/xattr.c +3 -1
-                        struct buffer_head *bh)
+                        struct buffer_head *bh,
+                        struct ext4_xattr_inode_array **ea_inode_array,
+                        int extra_credits)
{
       struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
       u32 hash, ref;
fs/ext4/xattr.c +238 -130
@@ -808,6 +1116,14 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
               mb_cache_entry_delete(ext4_mb_cache, hash, bh->b_blocknr);
               get_bh(bh);
               unlock_buffer(bh);
+
+               if (ext4_has_feature_ea_inode(inode->i_sb))
+                       ext4_xattr_inode_dec_ref_all(handle, inode, bh,
+                                                    BFIRST(bh),
+                                                    true /* block_csum */,
+                                                    ea_inode_array,
+                                                    extra_credits,
+                                                    true /* skip_quota */);
               ext4_free_blocks(handle, inode, bh, 0, 1,
                                EXT4_FREE_BLOCKS_METADATA |
                                EXT4_FREE_BLOCKS_FORGET);
@@ -879,8 +1195,8 @@ static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
 {
       struct buffer_head *bh = NULL;
       unsigned long block = 0;
-       unsigned blocksize = ea_inode->i_sb->s_blocksize;
-       unsigned max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
+       int blocksize = ea_inode->i_sb->s_blocksize;
+       int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits;
       int csize, wsize = 0;
       int ret = 0;
       int retries = 0;
@@ -948,7 +1264,7 @@ static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode,
 * Create an inode to store the value of a large EA.
 */
 static struct inode *ext4_xattr_inode_create(handle_t *handle,
-                                            struct inode *inode)
+                                            struct inode *inode, u32 hash)
 {
       struct inode *ea_inode = NULL;
       uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) };
@@ -966,67 +1282,115 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
               ea_inode->i_fop = &ext4_file_operations;
               ext4_set_aops(ea_inode);
               ext4_xattr_inode_set_class(ea_inode);
-               ea_inode->i_generation = inode->i_generation;
-               EXT4_I(ea_inode)->i_flags |= EXT4_EA_INODE_FL;
-
-               /*
-                * A back-pointer from EA inode to parent inode will be useful
-                * for e2fsck.
-                */
-               EXT4_XATTR_INODE_SET_PARENT(ea_inode, inode->i_ino);
               unlock_new_inode(ea_inode);
-               err = ext4_inode_attach_jinode(ea_inode);
+               ext4_xattr_inode_set_ref(ea_inode, 1);
+               ext4_xattr_inode_set_hash(ea_inode, hash);
+               err = ext4_mark_inode_dirty(handle, ea_inode);
+               if (!err)
+                       err = ext4_inode_attach_jinode(ea_inode);
               if (err) {
                       iput(ea_inode);
                       return ERR_PTR(err);
               }
+
+               /*
+                * Xattr inodes are shared therefore quota charging is performed
+                * at a higher level.
+                */
+               dquot_free_inode(ea_inode);
+               dquot_drop(ea_inode);
+               inode_lock(ea_inode);
+               ea_inode->i_flags |= S_NOQUOTA;
+               inode_unlock(ea_inode);
       }
 
       return ea_inode;
 }
 
-/*
- * Unlink the inode storing the value of the EA.
- */
-int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino)
+static struct inode *
+ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
+                           size_t value_len, u32 hash)
 {
-       struct inode *ea_inode = NULL;
-       int err;
+       struct inode *ea_inode;
+       struct mb_cache_entry *ce;
+       struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode);
+       void *ea_data;
 
-       err = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
-       if (err)
-               return err;
+       ce = mb_cache_entry_find_first(ea_inode_cache, hash);
+       if (!ce)
+               return NULL;
 
-       clear_nlink(ea_inode);
-       iput(ea_inode);
+       ea_data = ext4_kvmalloc(value_len, GFP_NOFS);
+       if (!ea_data) {
+               mb_cache_entry_put(ea_inode_cache, ce);
+               return NULL;
+       }
 
-       return 0;
+       while (ce) {
+               ea_inode = ext4_iget(inode->i_sb, ce->e_value);
+               if (!IS_ERR(ea_inode) &&
+                   !is_bad_inode(ea_inode) &&
+                   (EXT4_I(ea_inode)->i_flags & EXT4_EA_INODE_FL) &&
+                   i_size_read(ea_inode) == value_len &&
+                   !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
+                   !ext4_xattr_inode_verify_hash(ea_inode, ea_data,
+                                                 value_len) &&
+                   !memcmp(value, ea_data, value_len)) {
+                       mb_cache_entry_touch(ea_inode_cache, ce);
+                       mb_cache_entry_put(ea_inode_cache, ce);
+                       kvfree(ea_data);
+                       return ea_inode;
+               }
+
+               if (!IS_ERR(ea_inode))
+                       iput(ea_inode);
+               ce = mb_cache_entry_find_next(ea_inode_cache, ce);
+       }
+       kvfree(ea_data);
+       return NULL;
 }
 
 /*
 * Add value of the EA in an inode.
 */
-static int ext4_xattr_inode_set(handle_t *handle, struct inode *inode,
-                               unsigned long *ea_ino, const void *value,
-                               size_t value_len)
+static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode,
+                                         const void *value, size_t value_len,
+                                         struct inode **ret_inode)
 {
       struct inode *ea_inode;
+       u32 hash;
       int err;
 
+       hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len);
+       ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash);
+       if (ea_inode) {
+               err = ext4_xattr_inode_inc_ref(handle, ea_inode);
+               if (err) {
+                       iput(ea_inode);
+                       return err;
+               }
+
+               *ret_inode = ea_inode;
+               return 0;
+       }
+
       /* Create an inode for the EA value */
-       ea_inode = ext4_xattr_inode_create(handle, inode);
+       ea_inode = ext4_xattr_inode_create(handle, inode, hash);
       if (IS_ERR(ea_inode))
               return PTR_ERR(ea_inode);
 
       err = ext4_xattr_inode_write(handle, ea_inode, value, value_len);
-       if (err)
-               clear_nlink(ea_inode);
-       else
-               *ea_ino = ea_inode->i_ino;
+       if (err) {
+               ext4_xattr_inode_dec_ref(handle, ea_inode);
+               iput(ea_inode);
+               return err;
+       }
 
-       iput(ea_inode);
+       mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash,
+                             ea_inode->i_ino, true /* reusable */);
 
-       return err;
+       *ret_inode = ea_inode;
+       return 0;
 }
 
 static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
@@ -1034,9 +1398,37 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
                               handle_t *handle, struct inode *inode)
 {
       struct ext4_xattr_entry *last;
-       size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
+       struct ext4_xattr_entry *here = s->here;
+       size_t min_offs = s->end - s->base, name_len = strlen(i->name);
       int in_inode = i->in_inode;
-       int rc;
+       struct inode *old_ea_inode = NULL;
+       struct inode *new_ea_inode = NULL;
+       size_t old_size, new_size;
+       int ret;
+
+       /* Space used by old and new values. */
+       old_size = (!s->not_found && !here->e_value_inum) ?
+                       EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0;
+       new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0;
+
+       /*
+        * Optimization for the simple case when old and new values have the
+        * same padded sizes. Not applicable if external inodes are involved.
+        */
+       if (new_size && new_size == old_size) {
+               size_t offs = le16_to_cpu(here->e_value_offs);
+               void *val = s->base + offs;
+
+               here->e_value_size = cpu_to_le32(i->value_len);
+               if (i->value == EXT4_ZERO_XATTR_VALUE) {
+                       memset(val, 0, new_size);
+               } else {
+                       memcpy(val, i->value, i->value_len);
+                       /* Clear padding bytes. */
+                       memset(val + i->value_len, 0, new_size - i->value_len);
+               }
+               return 0;
+       }
 
       /* Compute min_offs and last. */
       last = s->first;
@@ -1047,122 +1439,148 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
                               min_offs = offs;
               }
       }
-       free = min_offs - ((void *)last - s->base) - sizeof(__u32);
-       if (!s->not_found) {
-               if (!in_inode &&
-                   !s->here->e_value_inum && s->here->e_value_size) {
-                       size_t size = le32_to_cpu(s->here->e_value_size);
-                       free += EXT4_XATTR_SIZE(size);
-               }
-               free += EXT4_XATTR_LEN(name_len);
-       }
+
+       /* Check whether we have enough space. */
       if (i->value) {
-               size_t value_len = EXT4_XATTR_SIZE(i->value_len);
+               size_t free;
 
-               if (in_inode)
-                       value_len = 0;
+               free = min_offs - ((void *)last - s->base) - sizeof(__u32);
+               if (!s->not_found)
+                       free += EXT4_XATTR_LEN(name_len) + old_size;
 
-               if (free < EXT4_XATTR_LEN(name_len) + value_len)
-                       return -ENOSPC;
+               if (free < EXT4_XATTR_LEN(name_len) + new_size) {
+                       ret = -ENOSPC;
+                       goto out;
+               }
       }
 
-       if (i->value && s->not_found) {
-               /* Insert the new name. */
-               size_t size = EXT4_XATTR_LEN(name_len);
-               size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
-               memmove((void *)s->here + size, s->here, rest);
-               memset(s->here, 0, size);
-               s->here->e_name_index = i->name_index;
-               s->here->e_name_len = name_len;
-               memcpy(s->here->e_name, i->name, name_len);
-       } else {
-               if (!s->here->e_value_inum && s->here->e_value_size &&
-                   s->here->e_value_offs > 0) {
-                       void *first_val = s->base + min_offs;
-                       size_t offs = le16_to_cpu(s->here->e_value_offs);
-                       void *val = s->base + offs;
-                       size_t size = EXT4_XATTR_SIZE(
-                               le32_to_cpu(s->here->e_value_size));
-
-                       if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
-                               /* The old and the new value have the same
-                                  size. Just replace. */
-                               s->here->e_value_size =
-                                       cpu_to_le32(i->value_len);
-                               if (i->value == EXT4_ZERO_XATTR_VALUE) {
-                                       memset(val, 0, size);
-                               } else {
-                                       /* Clear pad bytes first. */
-                                       memset(val + size - EXT4_XATTR_PAD, 0,
-                                              EXT4_XATTR_PAD);
-                                       memcpy(val, i->value, i->value_len);
-                               }
-                               return 0;
-                       }
+       /*
+        * Getting access to old and new ea inodes is subject to failures.
+        * Finish that work before doing any modifications to the xattr data.
+        */
+       if (!s->not_found && here->e_value_inum) {
+               ret = ext4_xattr_inode_iget(inode,
+                                           le32_to_cpu(here->e_value_inum),
+                                           &old_ea_inode);
+               if (ret) {
+                       old_ea_inode = NULL;
+                       goto out;
+               }
+       }
+       if (i->value && in_inode) {
+               WARN_ON_ONCE(!i->value_len);
 
-                       /* Remove the old value. */
-                       memmove(first_val + size, first_val, val - first_val);
-                       memset(first_val, 0, size);
-                       s->here->e_value_size = 0;
-                       s->here->e_value_offs = 0;
-                       min_offs += size;
-
-                       /* Adjust all value offsets. */
-                       last = s->first;
-                       while (!IS_LAST_ENTRY(last)) {
-                               size_t o = le16_to_cpu(last->e_value_offs);
-                               if (!last->e_value_inum &&
-                                   last->e_value_size && o < offs)
-                                       last->e_value_offs =
-                                               cpu_to_le16(o + size);
-                               last = EXT4_XATTR_NEXT(last);
-                       }
+               ret = ext4_xattr_inode_alloc_quota(inode, i->value_len);
+               if (ret)
+                       goto out;
+
+               ret = ext4_xattr_inode_lookup_create(handle, inode, i->value,
+                                                    i->value_len,
+                                                    &new_ea_inode);
+               if (ret) {
+                       new_ea_inode = NULL;
+                       ext4_xattr_inode_free_quota(inode, i->value_len);
+                       goto out;
               }
-               if (s->here->e_value_inum) {
-                       ext4_xattr_inode_unlink(inode,
-                                           le32_to_cpu(s->here->e_value_inum));
-                       s->here->e_value_inum = 0;
+       }
+
+       if (old_ea_inode) {
+               /* We are ready to release ref count on the old_ea_inode. */
+               ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode);
+               if (ret) {
+                       /* Release newly required ref count on new_ea_inode. */
+                       if (new_ea_inode) {
+                               int err;
+
+                               err = ext4_xattr_inode_dec_ref(handle,
+                                                              new_ea_inode);
+                               if (err)
+                                       ext4_warning_inode(new_ea_inode,
+                                                 "dec ref new_ea_inode err=%d",
+                                                 err);
+                               ext4_xattr_inode_free_quota(inode,
+                                                           i->value_len);
+                       }
+                       goto out;
               }
-               if (!i->value) {
-                       /* Remove the old name. */
-                       size_t size = EXT4_XATTR_LEN(name_len);
-                       last = ENTRY((void *)last - size);
-                       memmove(s->here, (void *)s->here + size,
-                               (void *)last - (void *)s->here + sizeof(__u32));
-                       memset(last, 0, size);
+
+               ext4_xattr_inode_free_quota(inode,
+                                           le32_to_cpu(here->e_value_size));
+       }
+
+       /* No failures allowed past this point. */
+
+       if (!s->not_found && here->e_value_offs) {
+               /* Remove the old value. */
+               void *first_val = s->base + min_offs;
+               size_t offs = le16_to_cpu(here->e_value_offs);
+               void *val = s->base + offs;
+
+               memmove(first_val + old_size, first_val, val - first_val);
+               memset(first_val, 0, old_size);
+               min_offs += old_size;
+
+               /* Adjust all value offsets. */
+               last = s->first;
+               while (!IS_LAST_ENTRY(last)) {
+                       size_t o = le16_to_cpu(last->e_value_offs);
+
+                       if (!last->e_value_inum &&
+                           last->e_value_size && o < offs)
+                               last->e_value_offs = cpu_to_le16(o + old_size);
+                       last = EXT4_XATTR_NEXT(last);
               }
       }
 
+       if (!i->value) {
+               /* Remove old name. */
+               size_t size = EXT4_XATTR_LEN(name_len);
+
+               last = ENTRY((void *)last - size);
+               memmove(here, (void *)here + size,
+                       (void *)last - (void *)here + sizeof(__u32));
+               memset(last, 0, size);
+       } else if (s->not_found) {
+               /* Insert new name. */
+               size_t size = EXT4_XATTR_LEN(name_len);
+               size_t rest = (void *)last - (void *)here + sizeof(__u32);
+
+               memmove((void *)here + size, here, rest);
+               memset(here, 0, size);
+               here->e_name_index = i->name_index;
+               here->e_name_len = name_len;
+               memcpy(here->e_name, i->name, name_len);
+       } else {
+               /* This is an update, reset value info. */
+               here->e_value_inum = 0;
+               here->e_value_offs = 0;
+               here->e_value_size = 0;
+       }
+
       if (i->value) {
-               /* Insert the new value. */
+               /* Insert new value. */
               if (in_inode) {
-                       unsigned long ea_ino =
-                               le32_to_cpu(s->here->e_value_inum);
-                       rc = ext4_xattr_inode_set(handle, inode, &ea_ino,
-                                                 i->value, i->value_len);
-                       if (rc)
-                               goto out;
-                       s->here->e_value_inum = cpu_to_le32(ea_ino);
-                       s->here->e_value_offs = 0;
+                       here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino);
               } else if (i->value_len) {
-                       size_t size = EXT4_XATTR_SIZE(i->value_len);
-                       void *val = s->base + min_offs - size;
-                       s->here->e_value_offs = cpu_to_le16(min_offs - size);
-                       s->here->e_value_inum = 0;
+                       void *val = s->base + min_offs - new_size;
+
+                       here->e_value_offs = cpu_to_le16(min_offs - new_size);
                       if (i->value == EXT4_ZERO_XATTR_VALUE) {
-                               memset(val, 0, size);
+                               memset(val, 0, new_size);
                       } else {
-                               /* Clear the pad bytes first. */
-                               memset(val + size - EXT4_XATTR_PAD, 0,
-                                      EXT4_XATTR_PAD);
                               memcpy(val, i->value, i->value_len);
+                               /* Clear padding bytes. */
+                               memset(val + i->value_len, 0,
+                                      new_size - i->value_len);
                       }
               }
-               s->here->e_value_size = cpu_to_le32(i->value_len);
+               here->e_value_size = cpu_to_le32(i->value_len);
       }
-
+       ret = 0;

out:

fs/ext4/xattr.c +3 -1
-       return rc;
+       iput(old_ea_inode);
+       iput(new_ea_inode);
+       return ret;

}

struct ext4_xattr_block_find {

fs/ext4/xattr.c +65 -2
@@ -1224,6 +1642,8 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
       struct mb_cache_entry *ce = NULL;
       int error = 0;
       struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
+       struct inode *ea_inode = NULL;
+       size_t old_ea_inode_size = 0;
 
 #define header(x) ((struct ext4_xattr_header *)(x))
 
@@ -1278,6 +1698,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                       header(s->base)->h_refcount = cpu_to_le32(1);
                       s->here = ENTRY(s->base + offset);
                       s->end = s->base + bs->bh->b_size;
+
+                       /*
+                        * If existing entry points to an xattr inode, we need
+                        * to prevent ext4_xattr_set_entry() from decrementing
+                        * ref count on it because the reference belongs to the
+                        * original block. In this case, make the entry look
+                        * like it has an empty value.
+                        */
+                       if (!s->not_found && s->here->e_value_inum) {
+                               /*
+                                * Defer quota free call for previous inode
+                                * until success is guaranteed.
+                                */
+                               old_ea_inode_size = le32_to_cpu(
+                                                       s->here->e_value_size);
+                               s->here->e_value_inum = 0;
+                               s->here->e_value_size = 0;
+                       }
               }
       } else {
               /* Allocate a buffer where we construct the new block. */
@@ -1299,6 +1737,24 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
               goto bad_block;
       if (error)
               goto cleanup;
+
+       if (i->value && s->here->e_value_inum) {
+               unsigned int ea_ino;
+
+               /*
+                * A ref count on ea_inode has been taken as part of the call to
+                * ext4_xattr_set_entry() above. We would like to drop this
+                * extra ref but we have to wait until the xattr block is
+                * initialized and has its own ref count on the ea_inode.
+                */
+               ea_ino = le32_to_cpu(s->here->e_value_inum);
+               error = ext4_xattr_inode_iget(inode, ea_ino, &ea_inode);
+               if (error) {
+                       ea_inode = NULL;
+                       goto cleanup;
+               }
+       }
+
       if (!IS_LAST_ENTRY(s->first))
               ext4_xattr_rehash(header(s->base), s->here);
 
@@ -1409,6 +1865,22 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
                                                EXT4_FREE_BLOCKS_METADATA);
                               goto cleanup;
                       }
+                       error = ext4_xattr_inode_inc_ref_all(handle, inode,
+                                                     ENTRY(header(s->base)+1));
+                       if (error)
+                               goto getblk_failed;
+                       if (ea_inode) {
+                               /* Drop the extra ref on ea_inode. */
+                               error = ext4_xattr_inode_dec_ref(handle,
+                                                                ea_inode);
+                               if (error)
+                                       ext4_warning_inode(ea_inode,
+                                                          "dec ref error=%d",
+                                                          error);
+                               iput(ea_inode);
+                               ea_inode = NULL;
+                       }
+
                       lock_buffer(new_bh);
                       error = ext4_journal_get_create_access(handle, new_bh);
                       if (error) {
@@ -1428,15 +1900,38 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
               }
       }
 
+       if (old_ea_inode_size)
+               ext4_xattr_inode_free_quota(inode, old_ea_inode_size);
+
       /* Update the inode. */
       EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
 
       /* Drop the previous xattr block. */
-       if (bs->bh && bs->bh != new_bh)
-               ext4_xattr_release_block(handle, inode, bs->bh);
+       if (bs->bh && bs->bh != new_bh) {
+               struct ext4_xattr_inode_array *ea_inode_array = NULL;
+
+               ext4_xattr_release_block(handle, inode, bs->bh,
+                                        &ea_inode_array,
+                                        0 /* extra_credits */);
+               ext4_xattr_inode_array_free(ea_inode_array);
+       }
       error = 0;
 

cleanup:

fs/ext4/xattr.c +58 -23
+       if (ea_inode) {
+               int error2;
+
+               error2 = ext4_xattr_inode_dec_ref(handle, ea_inode);
+               if (error2)
+                       ext4_warning_inode(ea_inode, "dec ref error=%d",
+                                          error2);
+
+               /* If there was an error, revert the quota charge. */
+               if (error)
+                       ext4_xattr_inode_free_quota(inode,
+                                                   i_size_read(ea_inode));
+               iput(ea_inode);
+       }
       if (ce)
               mb_cache_entry_put(ext4_mb_cache, ce);
       brelse(new_bh);
@@ -1561,6 +2056,22 @@ static int ext4_xattr_value_same(struct ext4_xattr_search *s,
       return !memcmp(value, i->value, i->value_len);
 }
 
+static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
+{
+       struct buffer_head *bh;
+       int error;
+
+       if (!EXT4_I(inode)->i_file_acl)
+               return NULL;
+       bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+       if (!bh)
+               return ERR_PTR(-EIO);
+       error = ext4_xattr_check_block(inode, bh);
+       if (error)
+               return ERR_PTR(error);
+       return bh;
+}
+
 /*
 * ext4_xattr_set_handle()
 *
@@ -1603,9 +2114,18 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 
       /* Check journal credits under write lock. */
       if (ext4_handle_valid(handle)) {
+               struct buffer_head *bh;
               int credits;
 
-               credits = ext4_xattr_set_credits(inode, value_len);
+               bh = ext4_xattr_get_block(inode);
+               if (IS_ERR(bh)) {
+                       error = PTR_ERR(bh);
+                       goto cleanup;
+               }
+
+               credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+               brelse(bh);
+
               if (!ext4_handle_has_enough_credits(handle, credits)) {
                       error = -ENOSPC;
                       goto cleanup;
@@ -1641,6 +2161,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
               if (flags & XATTR_CREATE)
                       goto cleanup;
       }
+
       if (!value) {
               if (!is.s.not_found)
                       error = ext4_xattr_ibody_set(handle, inode, &i, &is);
@@ -1709,34 +2230,29 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
       return error;
 }
 
-int ext4_xattr_set_credits(struct inode *inode, size_t value_len)
+int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
 {
-       struct super_block *sb = inode->i_sb;
-       int credits;
-
-       if (!EXT4_SB(sb)->s_journal)
-               return 0;
+       struct buffer_head *bh;
+       int err;
 
-       credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+       *credits = 0;
 
-       /*
-        * In case of inline data, we may push out the data to a block,
-        * so we need to reserve credits for this eventuality
-        */
-       if (ext4_has_inline_data(inode))
-               credits += ext4_writepage_trans_blocks(inode) + 1;
-
-       if (ext4_has_feature_ea_inode(sb)) {
-               int nrblocks = (value_len + sb->s_blocksize - 1) >>
-                                       sb->s_blocksize_bits;
+       if (!EXT4_SB(inode->i_sb)->s_journal)
+               return 0;
 
-               /* For new inode */
-               credits += EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + 3;
+       down_read(&EXT4_I(inode)->xattr_sem);
 
-               /* For data blocks of EA inode */
-               credits += ext4_meta_trans_blocks(inode, nrblocks, 0);
+       bh = ext4_xattr_get_block(inode);
+       if (IS_ERR(bh)) {
+               err = PTR_ERR(bh);
+       } else {
+               *credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+               brelse(bh);
+               err = 0;
       }
-       return credits;
+
+       up_read(&EXT4_I(inode)->xattr_sem);
+       return err;
 }
 
 /*
@@ -1761,7 +2277,10 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
               return error;
 

retry:

fs/ext4/xattr.c +69 -63
-       credits = ext4_xattr_set_credits(inode, value_len);
+       error = ext4_xattr_set_credits(inode, value_len, &credits);
+       if (error)
+               return error;
+
       handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
       if (IS_ERR(handle)) {
               error = PTR_ERR(handle);
@@ -2067,10 +2586,10 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
       return error;
 }
 
-
 #define EIA_INCR 16 /* must be 2^n */
 #define EIA_MASK (EIA_INCR - 1)
-/* Add the large xattr @inode into @ea_inode_array for later deletion.
+
+/* Add the large xattr @inode into @ea_inode_array for deferred iput().
 * If @ea_inode_array is new or full it will be grown and the old
 * contents copied over.
 */
@@ -2115,21 +2634,19 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 * ext4_xattr_delete_inode()
 *
 * Free extended attribute resources associated with this inode. Traverse
- * all entries and unlink any xattr inodes associated with this inode. This
- * is called immediately before an inode is freed. We have exclusive
- * access to the inode. If an orphan inode is deleted it will also delete any
- * xattr block and all xattr inodes. They are checked by ext4_xattr_inode_iget()
- * to ensure they belong to the parent inode and were not deleted already.
+ * all entries and decrement reference on any xattr inodes associated with this
+ * inode. This is called immediately before an inode is freed. We have exclusive
+ * access to the inode. If an orphan inode is deleted it will also release its
+ * references on xattr block and xattr inodes.
 */
-int
-ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
-                       struct ext4_xattr_inode_array **ea_inode_array,
-                       int extra_credits)
+int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
+                           struct ext4_xattr_inode_array **ea_inode_array,
+                           int extra_credits)
 {
       struct buffer_head *bh = NULL;
       struct ext4_xattr_ibody_header *header;
-       struct ext4_inode *raw_inode;
       struct ext4_iloc iloc = { .bh = NULL };
+       struct ext4_xattr_entry *entry;
       int error;
 
       error = ext4_xattr_ensure_credits(handle, inode, extra_credits,
@@ -2141,66 +2658,71 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
               goto cleanup;
       }
 
-       if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
-               goto delete_external_ea;
+       if (ext4_has_feature_ea_inode(inode->i_sb) &&
+           ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 
-       error = ext4_get_inode_loc(inode, &iloc);
-       if (error)
-               goto cleanup;
-
-       error = ext4_journal_get_write_access(handle, iloc.bh);
-       if (error)
-               goto cleanup;
+               error = ext4_get_inode_loc(inode, &iloc);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "inode loc (error %d)", error);
+                       goto cleanup;
+               }
 
-       raw_inode = ext4_raw_inode(&iloc);
-       header = IHDR(inode, raw_inode);
-       ext4_xattr_inode_remove_all(handle, inode, iloc.bh, IFIRST(header),
-                                   false /* block_csum */, ea_inode_array,
-                                   extra_credits);
+               error = ext4_journal_get_write_access(handle, iloc.bh);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "write access (error %d)",
+                                        error);
+                       goto cleanup;
+               }
 
-delete_external_ea:
-       if (!EXT4_I(inode)->i_file_acl) {
-               error = 0;
-               goto cleanup;
-       }
-       bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
-       if (!bh) {
-               EXT4_ERROR_INODE(inode, "block %llu read error",
-                                EXT4_I(inode)->i_file_acl);
-               error = -EIO;
-               goto cleanup;
-       }
-       if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
-           BHDR(bh)->h_blocks != cpu_to_le32(1)) {
-               EXT4_ERROR_INODE(inode, "bad block %llu",
-                                EXT4_I(inode)->i_file_acl);
-               error = -EFSCORRUPTED;
-               goto cleanup;
+               header = IHDR(inode, ext4_raw_inode(&iloc));
+               if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC))
+                       ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh,
+                                                    IFIRST(header),
+                                                    false /* block_csum */,
+                                                    ea_inode_array,
+                                                    extra_credits,
+                                                    false /* skip_quota */);
       }
 
-       if (ext4_has_feature_ea_inode(inode->i_sb)) {
-               error = ext4_journal_get_write_access(handle, bh);
-               if (error) {
-                       EXT4_ERROR_INODE(inode, "write access %llu",
+       if (EXT4_I(inode)->i_file_acl) {
+               bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+               if (!bh) {
+                       EXT4_ERROR_INODE(inode, "block %llu read error",
                                        EXT4_I(inode)->i_file_acl);
+                       error = -EIO;
+                       goto cleanup;
+               }
+               error = ext4_xattr_check_block(inode, bh);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "bad block %llu (error %d)",
+                                        EXT4_I(inode)->i_file_acl, error);
                       goto cleanup;
               }
-               ext4_xattr_inode_remove_all(handle, inode, bh,
-                                           BFIRST(bh),
-                                           true /* block_csum */,
-                                           ea_inode_array,
-                                           extra_credits);
-       }
 
-       ext4_xattr_release_block(handle, inode, bh);
-       /* Update i_file_acl within the same transaction that releases block. */
-       EXT4_I(inode)->i_file_acl = 0;
-       error = ext4_mark_inode_dirty(handle, inode);
-       if (error) {
-               EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
-                                error);
-               goto cleanup;
+               if (ext4_has_feature_ea_inode(inode->i_sb)) {
+                       for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+                            entry = EXT4_XATTR_NEXT(entry))
+                               if (entry->e_value_inum)
+                                       ext4_xattr_inode_free_quota(inode,
+                                             le32_to_cpu(entry->e_value_size));
+
+               }
+
+               ext4_xattr_release_block(handle, inode, bh, ea_inode_array,
+                                        extra_credits);
+               /*
+                * Update i_file_acl value in the same transaction that releases
+                * block.
+                */
+               EXT4_I(inode)->i_file_acl = 0;
+               error = ext4_mark_inode_dirty(handle, inode);
+               if (error) {
+                       EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)",
+                                        error);
+                       goto cleanup;
+               }
       }
+       error = 0;

cleanup:

       brelse(iloc.bh);
       brelse(bh);
fs/ext4/xattr.c +3 -7
@@ -2209,17 +2731,13 @@ ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
 
 void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array)
 {
-       struct inode    *ea_inode;
-       int             idx = 0;
+       int idx;
 
       if (ea_inode_array == NULL)
               return;
 
-       for (; idx < ea_inode_array->count; ++idx) {
-               ea_inode = ea_inode_array->inodes[idx];
-               clear_nlink(ea_inode);
-               iput(ea_inode);
-       }
+       for (idx = 0; idx < ea_inode_array->count; ++idx)
+               iput(ea_inode_array->inodes[idx]);
       kfree(ea_inode_array);
 }
 
fs/ext4/xattr.h +2 -15
index b2005a2716d9..67616cb9a059 100644
@@ -69,19 +69,6 @@ struct ext4_xattr_entry {
               EXT4_I(inode)->i_extra_isize))
 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
 
-/*
- * Link EA inode back to parent one using i_mtime field.
- * Extra integer type conversion added to ignore higher
- * bits in i_mtime.tv_sec which might be set by ext4_get()
- */
-#define EXT4_XATTR_INODE_SET_PARENT(inode, inum)      \
-do {                                                  \
-      (inode)->i_mtime.tv_sec = inum;                 \
-} while(0)
-
-#define EXT4_XATTR_INODE_GET_PARENT(inode)            \
-((__u32)(inode)->i_mtime.tv_sec)
-
 /*
 * The minimum size of EA value when you start storing it in an external inode
 * size of block - size of header - size of 1 entry - 4 null bytes
@@ -165,9 +152,9 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
-extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
+                                 int *credits);
 
-extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
                                  struct ext4_xattr_inode_array **array,
                                  int extra_credits);
fs/mbcache.c +3 -4
index 45a8d52dc991..d818fd236787 100644
@@ -13,10 +13,11 @@
 * mb_cache_entry_delete()).
 *
 * Ext2 and ext4 use this cache for deduplication of extended attribute blocks.
- * They use hash of a block contents as a key and block number as a value.
- * That's why keys need not be unique (different xattr blocks may end up having
- * the same hash). However block number always uniquely identifies a cache
- * entry.
+ * Ext4 also uses it for deduplication of xattr values stored in inodes.
+ * They use hash of data as a key and provide a value that may represent a
+ * block or inode number. That's why keys need not be unique (hash of different
Quoted 8 lines
Quoted 8 lines
fs/mbcache.c +2 -1
+ * data may be the same). However user provided value always uniquely
+ * identifies a cache entry.
 *
 * We provide functions for creation and removal of entries, search by key,
 * and a special "delete entry with given key-value pair" operation. Fixed
--

2.13.1.518.g3df882009-goog

Cheers, Andreas

#58 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

In reply to Tahsin Erdogan
Quoted 29 lines · Tahsin Erdogan

Ext4 now supports xattr values that are up to 64k in size (vfs limit). Large xattr values are stored in external inodes each one holding a single value. Once written the data blocks of these inodes are immutable.

The real world use cases are expected to have a lot of value duplication such as inherited acls etc. To reduce data duplication on disk, this patch implements a deduplicator that allows sharing of xattr inodes.

The deduplication is based on an in-memory hash lookup that is a best effort sharing scheme. When a xattr inode is read from disk (i.e. getxattr() call), its crc32c hash is added to a hash table. Before creating a new xattr inode for a value being set, the hash table is checked to see if an existing inode holds an identical value. If such an inode is found, the ref count on that inode is incremented. On value removal the ref count is decremented and if it reaches zero the inode is deleted.

The quota charging for such inodes is manually managed. Every reference holder is charged the full size as if there was no sharing happening. This is consistent with how xattr blocks are also charged.

---

fs/ext4/ext4.h +0 -0
index d79d8d7bee88..59e9488c4876 100644

fs/ext4/ext4.h struct ext4_sb_info { · line 1520

Quoted 4 lines
fs/ext4/ext4.h +1 -0
@@ -1517,6 +1517,7 @@ struct ext4_sb_info {
 	long s_es_nr_inode;
 	struct ext4_es_stats s_es_stats;
 	struct mb_cache *s_mb_cache;
+	struct mb_cache *s_ea_inode_cache;

These names should be consistent, like "s_ea_block_cache".

fs/ext4/xattr.c const struct xattr_handler *ext4_xattr_handlers[] = { · line 112

Quoted 10 lines
fs/ext4/xattr.c +2 -0
index 0484df8dadd1..d7e60358ec91 100644
@@ -108,6 +108,9 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
 #define EXT4_GET_MB_CACHE(inode)	(((struct ext4_sb_info *) \
 				inode->i_sb->s_fs_info)->s_mb_cache)
 
+#define EA_INODE_CACHE(inode)	(((struct ext4_sb_info *) \
+				inode->i_sb->s_fs_info)->s_ea_inode_cache)

These names should be consistent, like EXT4_GET_EA_CACHE() or maybe EXT4_GET_EA_BLOCK_CACHE() and EXT4_GET_EA_INODE_CACHE().

The rest of the changes look reasonable.

Cheers, Andreas

#59 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

Quoted 3 lines

Tashin, we are already using the "no_mbcache" option name, so would prefer to keep that working. It would be OK to accept both option names to mean the same thing, and only document the "nombcache" option.

Updated patch to accept both nombcache and no_mbcache.

Quoted 4 lines
Quoted 2 lines
      struct mb_cache *s_mb_cache;

+ struct mb_cache *s_ea_inode_cache;

These names should be consistent, like "s_ea_block_cache".

Yes, I will rename this to s_ea_block_cache.

Quoted 8 lines

fs/ext4/xattr.c const struct xattr_handler *ext4_xattr_handlers[] = { · line 112

Quoted 5 lines
#define EXT4_GET_MB_CACHE(inode)      (((struct ext4_sb_info *) \
                              inode->i_sb->s_fs_info)->s_mb_cache)
fs/ext4/xattr.c +2 -0
+#define EA_INODE_CACHE(inode)        (((struct ext4_sb_info *) \
+                             inode->i_sb->s_fs_info)->s_ea_inode_cache)

These names should be consistent, like EXT4_GET_EA_CACHE() or maybe EXT4_GET_EA_BLOCK_CACHE() and EXT4_GET_EA_INODE_CACHE().

How about EA_BLOCK_CACHE() and EA_INODE_CACHE() to keep them short?

#60 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

Quoted 19 lines · Tahsin Erdogan
Quoted 4 lines

Tashin, we are already using the "no_mbcache" option name, so would prefer to keep that working. It would be OK to accept both option names to mean the same thing, and only document the "nombcache" option.

Updated patch to accept both nombcache and no_mbcache.

Quoted 4 lines
Quoted 2 lines
     struct mb_cache *s_mb_cache;

+ struct mb_cache *s_ea_inode_cache;

These names should be consistent, like "s_ea_block_cache".

Yes, I will rename this to s_ea_block_cache.

Quoted 3 lines
Quoted 3 lines
#define EXT4_GET_MB_CACHE(inode)      (((struct ext4_sb_info *) \
                             inode->i_sb->s_fs_info)->s_mb_cache)
Quoted 7 lines
Quoted 5 lines

fs/ext4/xattr.c const struct xattr_handler *ext4_xattr_handlers[] = { · line 112

Quoted 2 lines
fs/ext4/xattr.c +2 -0
+#define EA_INODE_CACHE(inode)        (((struct ext4_sb_info *) \
+                             inode->i_sb->s_fs_info)->s_ea_inode_cache)

These names should be consistent, like EXT4_GET_EA_CACHE() or maybe EXT4_GET_EA_BLOCK_CACHE() and EXT4_GET_EA_INODE_CACHE().

How about EA_BLOCK_CACHE() and EA_INODE_CACHE() to keep them short?

Sure, that is fine since these macros are local to xattr.c.

Cheers, Andreas

maintainer
#61 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

In reply to Tahsin Erdogan

I'm going to fold in the following patch to the xattr inode deduplicate patch to fix up some corner cases which __ext4_xattr_set_credits() wasn't quite getting right.

- Ted

fs/ext4/xattr.c +18 -4
index 4befc7369c0d..435a49811218 100644
@@ -762,10 +762,11 @@ static void ext4_xattr_inode_free_quota(struct inode *inode, size_t len)
 	dquot_free_inode(inode);
 }
 
-static int __ext4_xattr_set_credits(struct super_block *sb,
+static int __ext4_xattr_set_credits(struct inode *inode,
 				    struct buffer_head *block_bh,
 				    size_t value_len)
 {
+	struct super_block *sb = inode->i_sb;
 	int credits;
 	int blocks;
 
@@ -775,12 +776,25 @@ static int __ext4_xattr_set_credits(struct super_block *sb,
 	 * 3) new xattr block
 	 * 4) block bitmap update for new xattr block
 	 * 5) group descriptor for new xattr block
+	 * 6) block bitmap update for old xattr block
+	 * 7) group descriptor for new old block
+	 *
+	 * 6 & 7 can happen if we have two racing threads T_a and T_b
+	 * which are each trying to set an xattr on inodes I_a and I_b
+	 * which were both initially sharing an xattr block.
 	 */
-	credits = 5;
+	credits = 7;
 
 	/* Quota updates. */
 	credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb);
 
+	/*
+	 * In case of inline data, we may push out the data to a block,
+	 * so we need to reserve credits for this eventuality
+	 */
+	if (ext4_has_inline_data(inode))
+		credits += ext4_writepage_trans_blocks(inode) + 1;
+
 	/* We are done if ea_inode feature is not enabled. */
 	if (!ext4_has_feature_ea_inode(sb))
 		return credits;
@@ -2120,7 +2134,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 			goto cleanup;
 		}
 
-		credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+		credits = __ext4_xattr_set_credits(inode, bh, value_len);
 		brelse(bh);
 
 		if (!ext4_handle_has_enough_credits(handle, credits)) {
@@ -2243,7 +2257,7 @@ int ext4_xattr_set_credits(struct inode *inode, size_t value_len, int *credits)
 	if (IS_ERR(bh)) {
 		err = PTR_ERR(bh);
 	} else {
-		*credits = __ext4_xattr_set_credits(inode->i_sb, bh, value_len);
+		*credits = __ext4_xattr_set_credits(inode, bh, value_len);
 		brelse(bh);
 		err = 0;
 	}
#62 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

fs/ext4/xattr.c static int __ext4_xattr_set_credits(struct super_block *sb, · line 780

Quoted 3 lines

* 5) group descriptor for new xattr block

fs/ext4/xattr.c +2 -0
+        * 6) block bitmap update for old xattr block
+        * 7) group descriptor for new old block

s/new old block/old block/

maintainer
#63 lore raw

Re: [PATCH v5 27/28] ext4: xattr inode deduplication

Quoted 5 lines · Tahsin Erdogan

fs/ext4/xattr.c static int __ext4_xattr_set_credits(struct super_block *sb, · line 780

Quoted 3 lines

* 5) group descriptor for new xattr block

fs/ext4/xattr.c +2 -0
+        * 6) block bitmap update for old xattr block
+        * 7) group descriptor for new old block

s/new old block/old block/

Thanks, I've fixed that up in my tree.

- Ted

#64 lore raw

PATCH 28/28 quota: add extra inode count to dquot transfer functions

In reply to Tahsin Erdogan

Ext4 ea_inode feature allows storing xattr values in external inodes to be able to store values that are bigger than a block in size. Ext4 also has deduplication support for these type of inodes. With deduplication, the actual storage waste is eliminated but the users of such inodes are still charged full quota for the inodes as if there was no sharing happening in the background.

This design requires ext4 to manually charge the users because the inodes are shared.

An implication of this is that, if someone calls chown on a file that has such references we need to transfer the quota for the file and xattr inodes. Current dquot_transfer() function implicitly transfers one inode charge. In our case, we would like to specify additional inodes to be transferred.

---
 fs/ext2/inode.c          |  2 +-
 fs/ext4/inode.c          |  8 ++++++-
 fs/ext4/ioctl.c          | 13 +++++++++++-
 fs/ext4/xattr.c          | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/xattr.h          |  2 ++
 fs/jfs/file.c            |  2 +-
 fs/ocfs2/file.c          |  2 +-
 fs/quota/dquot.c         | 16 +++++++-------
 fs/reiserfs/inode.c      |  2 +-
 include/linux/quotaops.h |  8 ++++---
 10 files changed, 93 insertions(+), 16 deletions(-)
fs/ext2/inode.c +1 -1
index 2dcbd5698884..a13ba5dcb355 100644
@@ -1656,7 +1656,7 @@ int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
 	}
 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		error = dquot_transfer(inode, iattr);
+		error = dquot_transfer(inode, iattr, 0);
 		if (error)
 			return error;
 	}
fs/ext4/inode.c +7 -1
index 6f5872197d6c..28abbbdbbb80 100644
@@ -5267,6 +5267,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 	int error, rc = 0;
 	int orphan = 0;
 	const unsigned int ia_valid = attr->ia_valid;
+	int ea_inode_refs;
 
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 		return -EIO;
@@ -5293,7 +5294,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 			error = PTR_ERR(handle);
 			goto err_out;
 		}
-		error = dquot_transfer(inode, attr);
+
+		down_read(&EXT4_I(inode)->xattr_sem);
+		error = ea_inode_refs = ext4_xattr_inode_count(inode);
+		if (ea_inode_refs >= 0)
+			error = dquot_transfer(inode, attr, ea_inode_refs);
+		up_read(&EXT4_I(inode)->xattr_sem);
 		if (error) {
 			ext4_journal_stop(handle);
 			return error;
fs/ext4/ioctl.c +12 -1
index dde8deb11e59..9938dc8e24c8 100644
@@ -21,6 +21,7 @@
 #include "ext4.h"
 #include <linux/fsmap.h>
 #include "fsmap.h"
+#include "xattr.h"
 #include <trace/events/ext4.h>
 
 /**
@@ -319,6 +320,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	struct ext4_iloc iloc;
 	struct ext4_inode *raw_inode;
 	struct dquot *transfer_to[MAXQUOTAS] = { };
+	int ea_inode_refs;
 
 	if (!ext4_has_feature_project(sb)) {
 		if (projid != EXT4_DEF_PROJID)
@@ -371,9 +373,17 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	if (err)
 		goto out_stop;
 
+	down_read(&EXT4_I(inode)->xattr_sem);
+	ea_inode_refs = ext4_xattr_inode_count(inode);
+	if (ea_inode_refs < 0) {
+		up_read(&EXT4_I(inode)->xattr_sem);
+		err = ea_inode_refs;
+		goto out_stop;
+	}
+
 	transfer_to[PRJQUOTA] = dqget(sb, make_kqid_projid(kprojid));
 	if (!IS_ERR(transfer_to[PRJQUOTA])) {
-		err = __dquot_transfer(inode, transfer_to);
+		err = __dquot_transfer(inode, transfer_to, ea_inode_refs);
 		dqput(transfer_to[PRJQUOTA]);
 		if (err)
 			goto out_dirty;
@@ -382,6 +392,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	EXT4_I(inode)->i_projid = kprojid;
 	inode->i_ctime = current_time(inode);
 out_dirty:
+	up_read(&EXT4_I(inode)->xattr_sem);
 	rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
 	if (!err)
 		err = rc;
fs/ext4/xattr.c +54 -0

60 lines not on this page · raw message

fs/ext4/xattr.h +2 -0
index 67616cb9a059..8ef6fe123255 100644
@@ -193,3 +193,5 @@ extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
 #else
 static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
 #endif
+
+int ext4_xattr_inode_count(struct inode *inode);
fs/jfs/file.c +1 -1
index 739492c7a3fd..b08e0b0449a7 100644
@@ -114,7 +114,7 @@ int jfs_setattr(struct dentry *dentry, struct iattr *iattr)
 	}
 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		rc = dquot_transfer(inode, iattr);
+		rc = dquot_transfer(inode, iattr, 0);
 		if (rc)
 			return rc;
 	}
fs/ocfs2/file.c +1 -1
index bfeb647459d9..d3cbf6467af6 100644
@@ -1259,7 +1259,7 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
 			mlog_errno(status);
 			goto bail_unlock;
 		}
-		status = __dquot_transfer(inode, transfer_to);
+		status = __dquot_transfer(inode, transfer_to, 0);
 		if (status < 0)
 			goto bail_commit;
 	} else {
fs/quota/dquot.c +9 -7
index 48813aeaab80..16e13d554aaa 100644
@@ -1906,10 +1906,12 @@ EXPORT_SYMBOL(dquot_free_inode);
  * We are holding reference on transfer_from & transfer_to, no need to
  * protect them by srcu_read_lock().
  */
-int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
+int __dquot_transfer(struct inode *inode, struct dquot **transfer_to,
+		     int inodes_extra)
 {
 	qsize_t space, cur_space;
 	qsize_t rsv_space = 0;
+	qsize_t inode_count = 1 + inodes_extra;
 	struct dquot *transfer_from[MAXQUOTAS] = {};
 	int cnt, ret = 0;
 	char is_valid[MAXQUOTAS] = {};
@@ -1946,7 +1948,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 			continue;
 		is_valid[cnt] = 1;
 		transfer_from[cnt] = i_dquot(inode)[cnt];
-		ret = check_idq(transfer_to[cnt], 1, &warn_to[cnt]);
+		ret = check_idq(transfer_to[cnt], inode_count, &warn_to[cnt]);
 		if (ret)
 			goto over_quota;
 		ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]);
@@ -1963,7 +1965,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 		/* Due to IO error we might not have transfer_from[] structure */
 		if (transfer_from[cnt]) {
 			int wtype;
-			wtype = info_idq_free(transfer_from[cnt], 1);
+			wtype = info_idq_free(transfer_from[cnt], inode_count);
 			if (wtype != QUOTA_NL_NOWARN)
 				prepare_warning(&warn_from_inodes[cnt],
 						transfer_from[cnt], wtype);
@@ -1971,13 +1973,13 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 			if (wtype != QUOTA_NL_NOWARN)
 				prepare_warning(&warn_from_space[cnt],
 						transfer_from[cnt], wtype);
-			dquot_decr_inodes(transfer_from[cnt], 1);
+			dquot_decr_inodes(transfer_from[cnt], inode_count);
 			dquot_decr_space(transfer_from[cnt], cur_space);
 			dquot_free_reserved_space(transfer_from[cnt],
 						  rsv_space);
 		}
 
-		dquot_incr_inodes(transfer_to[cnt], 1);
+		dquot_incr_inodes(transfer_to[cnt], inode_count);
 		dquot_incr_space(transfer_to[cnt], cur_space);
 		dquot_resv_space(transfer_to[cnt], rsv_space);
 
@@ -2005,7 +2007,7 @@ EXPORT_SYMBOL(__dquot_transfer);
 /* Wrapper for transferring ownership of an inode for uid/gid only
  * Called from FSXXX_setattr()
  */
-int dquot_transfer(struct inode *inode, struct iattr *iattr)
+int dquot_transfer(struct inode *inode, struct iattr *iattr, int inodes_extra)
 {
 	struct dquot *transfer_to[MAXQUOTAS] = {};
 	struct dquot *dquot;
@@ -2037,7 +2039,7 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
 		}
 		transfer_to[GRPQUOTA] = dquot;
 	}
-	ret = __dquot_transfer(inode, transfer_to);
+	ret = __dquot_transfer(inode, transfer_to, inodes_extra);
 out_put:
 	dqput_all(transfer_to);
 	return ret;
fs/reiserfs/inode.c +1 -1
index 873fc04e9403..51586051b5dd 100644
@@ -3370,7 +3370,7 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
 		reiserfs_write_unlock(inode->i_sb);
 		if (error)
 			goto out;
-		error = dquot_transfer(inode, attr);
+		error = dquot_transfer(inode, attr, 0);
 		reiserfs_write_lock(inode->i_sb);
 		if (error) {
 			journal_end(&th);
include/linux/quotaops.h +5 -3
index dda22f45fc1b..b7bcd9c6db6c 100644
@@ -106,8 +106,9 @@ int dquot_get_next_dqblk(struct super_block *sb, struct kqid *id,
 int dquot_set_dqblk(struct super_block *sb, struct kqid id,
 		struct qc_dqblk *di);
 
-int __dquot_transfer(struct inode *inode, struct dquot **transfer_to);
-int dquot_transfer(struct inode *inode, struct iattr *iattr);
+int __dquot_transfer(struct inode *inode, struct dquot **transfer_to,
+		int inodes_extra);
+int dquot_transfer(struct inode *inode, struct iattr *iattr, int inodes_extra);
 
 static inline struct mem_dqinfo *sb_dqinfo(struct super_block *sb, int type)
 {
@@ -226,7 +227,8 @@ static inline void dquot_free_inode(struct inode *inode)
 {
 }
 
-static inline int dquot_transfer(struct inode *inode, struct iattr *iattr)
+static inline int dquot_transfer(struct inode *inode, struct iattr *iattr,
+		int inodes_extra)
 {
 	return 0;
 }
Signature · 1 line
2.13.0.219.gdb65acc882-goog
reviewer
#65 lore raw

Re: [PATCH 28/28] quota: add extra inode count to dquot transfer functions

Quoted 7 lines · Tahsin Erdogan

Ext4 ea_inode feature allows storing xattr values in external inodes to be able to store values that are bigger than a block in size. Ext4 also has deduplication support for these type of inodes. With deduplication, the actual storage waste is eliminated but the users of such inodes are still charged full quota for the inodes as if there was no sharing happening in the background.

Quoted 8 lines

This design requires ext4 to manually charge the users because the inodes are shared.

An implication of this is that, if someone calls chown on a file that has such references we need to transfer the quota for the file and xattr inodes. Current dquot_transfer() function implicitly transfers one inode charge. In our case, we would like to specify additional inodes to be transferred.

Hum, rather handle this similarly to how we handle delalloc reserved space. Add a callback to dq_ops to get "inode usage" of an inode and then use it in dquot_transfer(), dquot_free_inode(), dquot_alloc_inode().

Honza

Quoted 314 lines
---
 fs/ext2/inode.c          |  2 +-
 fs/ext4/inode.c          |  8 ++++++-
 fs/ext4/ioctl.c          | 13 +++++++++++-
 fs/ext4/xattr.c          | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/xattr.h          |  2 ++
 fs/jfs/file.c            |  2 +-
 fs/ocfs2/file.c          |  2 +-
 fs/quota/dquot.c         | 16 +++++++-------
 fs/reiserfs/inode.c      |  2 +-
 include/linux/quotaops.h |  8 ++++---
 10 files changed, 93 insertions(+), 16 deletions(-)
fs/ext2/inode.c +1 -1
index 2dcbd5698884..a13ba5dcb355 100644
@@ -1656,7 +1656,7 @@ int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
 	}
 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		error = dquot_transfer(inode, iattr);
+		error = dquot_transfer(inode, iattr, 0);
 		if (error)
 			return error;
 	}
fs/ext4/inode.c +7 -1
index 6f5872197d6c..28abbbdbbb80 100644
@@ -5267,6 +5267,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 	int error, rc = 0;
 	int orphan = 0;
 	const unsigned int ia_valid = attr->ia_valid;
+	int ea_inode_refs;
 
 	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
 		return -EIO;
@@ -5293,7 +5294,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 			error = PTR_ERR(handle);
 			goto err_out;
 		}
-		error = dquot_transfer(inode, attr);
+
+		down_read(&EXT4_I(inode)->xattr_sem);
+		error = ea_inode_refs = ext4_xattr_inode_count(inode);
+		if (ea_inode_refs >= 0)
+			error = dquot_transfer(inode, attr, ea_inode_refs);
+		up_read(&EXT4_I(inode)->xattr_sem);
 		if (error) {
 			ext4_journal_stop(handle);
 			return error;
fs/ext4/ioctl.c +12 -1
index dde8deb11e59..9938dc8e24c8 100644
@@ -21,6 +21,7 @@
 #include "ext4.h"
 #include <linux/fsmap.h>
 #include "fsmap.h"
+#include "xattr.h"
 #include <trace/events/ext4.h>
 
 /**
@@ -319,6 +320,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	struct ext4_iloc iloc;
 	struct ext4_inode *raw_inode;
 	struct dquot *transfer_to[MAXQUOTAS] = { };
+	int ea_inode_refs;
 
 	if (!ext4_has_feature_project(sb)) {
 		if (projid != EXT4_DEF_PROJID)
@@ -371,9 +373,17 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	if (err)
 		goto out_stop;
 
+	down_read(&EXT4_I(inode)->xattr_sem);
+	ea_inode_refs = ext4_xattr_inode_count(inode);
+	if (ea_inode_refs < 0) {
+		up_read(&EXT4_I(inode)->xattr_sem);
+		err = ea_inode_refs;
+		goto out_stop;
+	}
+
 	transfer_to[PRJQUOTA] = dqget(sb, make_kqid_projid(kprojid));
 	if (!IS_ERR(transfer_to[PRJQUOTA])) {
-		err = __dquot_transfer(inode, transfer_to);
+		err = __dquot_transfer(inode, transfer_to, ea_inode_refs);
 		dqput(transfer_to[PRJQUOTA]);
 		if (err)
 			goto out_dirty;
@@ -382,6 +392,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
 	EXT4_I(inode)->i_projid = kprojid;
 	inode->i_ctime = current_time(inode);
 out_dirty:
+	up_read(&EXT4_I(inode)->xattr_sem);
 	rc = ext4_mark_iloc_dirty(handle, inode, &iloc);
 	if (!err)
 		err = rc;
fs/ext4/xattr.c +54 -0
index caddc176a612..1d6fcbb01517 100644
@@ -701,6 +701,60 @@ static void ext4_xattr_update_super_block(handle_t *handle,
 	}
 }
 
+int ext4_xattr_inode_count(struct inode *inode)
+{
+	struct ext4_iloc iloc = { .bh = NULL };
+	struct buffer_head *bh = NULL;
+	struct ext4_inode *raw_inode;
+	struct ext4_xattr_ibody_header *header;
+	struct ext4_xattr_entry *entry;
+	int inode_count = 0;
+	void *end;
+	int ret;
+
+	lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem);
+
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
+		ret = ext4_get_inode_loc(inode, &iloc);
+		if (ret)
+			goto out;
+		raw_inode = ext4_raw_inode(&iloc);
+		header = IHDR(inode, raw_inode);
+		end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+		ret = xattr_check_inode(inode, header, end);
+		if (ret)
+			goto out;
+
+		for (entry = IFIRST(header); !IS_LAST_ENTRY(entry);
+		     entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				inode_count++;
+	}
+
+	if (EXT4_I(inode)->i_file_acl) {
+		bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+		if (!bh) {
+			ret = -EIO;
+			goto out;
+		}
+
+		if (ext4_xattr_check_block(inode, bh)) {
+			ret = -EFSCORRUPTED;
+			goto out;
+		}
+
+		for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry);
+		     entry = EXT4_XATTR_NEXT(entry))
+			if (entry->e_value_inum)
+				inode_count++;
+	}
+	ret = inode_count;
+out:
+	brelse(iloc.bh);
+	brelse(bh);
+	return ret;
+}
+
 static inline size_t round_up_cluster(struct inode *inode, size_t length)
 {
 	struct super_block *sb = inode->i_sb;
fs/ext4/xattr.h +2 -0
index 67616cb9a059..8ef6fe123255 100644
@@ -193,3 +193,5 @@ extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
 #else
 static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
 #endif
+
+int ext4_xattr_inode_count(struct inode *inode);
fs/jfs/file.c +1 -1
index 739492c7a3fd..b08e0b0449a7 100644
@@ -114,7 +114,7 @@ int jfs_setattr(struct dentry *dentry, struct iattr *iattr)
 	}
 	if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
 	    (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
-		rc = dquot_transfer(inode, iattr);
+		rc = dquot_transfer(inode, iattr, 0);
 		if (rc)
 			return rc;
 	}
fs/ocfs2/file.c +1 -1
index bfeb647459d9..d3cbf6467af6 100644
@@ -1259,7 +1259,7 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
 			mlog_errno(status);
 			goto bail_unlock;
 		}
-		status = __dquot_transfer(inode, transfer_to);
+		status = __dquot_transfer(inode, transfer_to, 0);
 		if (status < 0)
 			goto bail_commit;
 	} else {
fs/quota/dquot.c +9 -7
index 48813aeaab80..16e13d554aaa 100644
@@ -1906,10 +1906,12 @@ EXPORT_SYMBOL(dquot_free_inode);
  * We are holding reference on transfer_from & transfer_to, no need to
  * protect them by srcu_read_lock().
  */
-int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
+int __dquot_transfer(struct inode *inode, struct dquot **transfer_to,
+		     int inodes_extra)
 {
 	qsize_t space, cur_space;
 	qsize_t rsv_space = 0;
+	qsize_t inode_count = 1 + inodes_extra;
 	struct dquot *transfer_from[MAXQUOTAS] = {};
 	int cnt, ret = 0;
 	char is_valid[MAXQUOTAS] = {};
@@ -1946,7 +1948,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 			continue;
 		is_valid[cnt] = 1;
 		transfer_from[cnt] = i_dquot(inode)[cnt];
-		ret = check_idq(transfer_to[cnt], 1, &warn_to[cnt]);
+		ret = check_idq(transfer_to[cnt], inode_count, &warn_to[cnt]);
 		if (ret)
 			goto over_quota;
 		ret = check_bdq(transfer_to[cnt], space, 0, &warn_to[cnt]);
@@ -1963,7 +1965,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 		/* Due to IO error we might not have transfer_from[] structure */
 		if (transfer_from[cnt]) {
 			int wtype;
-			wtype = info_idq_free(transfer_from[cnt], 1);
+			wtype = info_idq_free(transfer_from[cnt], inode_count);
 			if (wtype != QUOTA_NL_NOWARN)
 				prepare_warning(&warn_from_inodes[cnt],
 						transfer_from[cnt], wtype);
@@ -1971,13 +1973,13 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
 			if (wtype != QUOTA_NL_NOWARN)
 				prepare_warning(&warn_from_space[cnt],
 						transfer_from[cnt], wtype);
-			dquot_decr_inodes(transfer_from[cnt], 1);
+			dquot_decr_inodes(transfer_from[cnt], inode_count);
 			dquot_decr_space(transfer_from[cnt], cur_space);
 			dquot_free_reserved_space(transfer_from[cnt],
 						  rsv_space);
 		}
 
-		dquot_incr_inodes(transfer_to[cnt], 1);
+		dquot_incr_inodes(transfer_to[cnt], inode_count);
 		dquot_incr_space(transfer_to[cnt], cur_space);
 		dquot_resv_space(transfer_to[cnt], rsv_space);
 
@@ -2005,7 +2007,7 @@ EXPORT_SYMBOL(__dquot_transfer);
 /* Wrapper for transferring ownership of an inode for uid/gid only
  * Called from FSXXX_setattr()
  */
-int dquot_transfer(struct inode *inode, struct iattr *iattr)
+int dquot_transfer(struct inode *inode, struct iattr *iattr, int inodes_extra)
 {
 	struct dquot *transfer_to[MAXQUOTAS] = {};
 	struct dquot *dquot;
@@ -2037,7 +2039,7 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
 		}
 		transfer_to[GRPQUOTA] = dquot;
 	}
-	ret = __dquot_transfer(inode, transfer_to);
+	ret = __dquot_transfer(inode, transfer_to, inodes_extra);
 out_put:
 	dqput_all(transfer_to);
 	return ret;
fs/reiserfs/inode.c +1 -1
index 873fc04e9403..51586051b5dd 100644
@@ -3370,7 +3370,7 @@ int reiserfs_setattr(struct dentry *dentry, struct iattr *attr)
 		reiserfs_write_unlock(inode->i_sb);
 		if (error)
 			goto out;
-		error = dquot_transfer(inode, attr);
+		error = dquot_transfer(inode, attr, 0);
 		reiserfs_write_lock(inode->i_sb);
 		if (error) {
 			journal_end(&th);
include/linux/quotaops.h +5 -3
index dda22f45fc1b..b7bcd9c6db6c 100644
@@ -106,8 +106,9 @@ int dquot_get_next_dqblk(struct super_block *sb, struct kqid *id,
 int dquot_set_dqblk(struct super_block *sb, struct kqid id,
 		struct qc_dqblk *di);
 
-int __dquot_transfer(struct inode *inode, struct dquot **transfer_to);
-int dquot_transfer(struct inode *inode, struct iattr *iattr);
+int __dquot_transfer(struct inode *inode, struct dquot **transfer_to,
+		int inodes_extra);
+int dquot_transfer(struct inode *inode, struct iattr *iattr, int inodes_extra);
 
 static inline struct mem_dqinfo *sb_dqinfo(struct super_block *sb, int type)
 {
@@ -226,7 +227,8 @@ static inline void dquot_free_inode(struct inode *inode)
 {
 }
 
-static inline int dquot_transfer(struct inode *inode, struct iattr *iattr)
+static inline int dquot_transfer(struct inode *inode, struct iattr *iattr,
+		int inodes_extra)
 {
 	return 0;
 }
Signature · 1 line
2.13.0.219.gdb65acc882-goog
Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR